Dr. Willis's practice of physick being the whole works of that renowned and famous physician wherein most of the diseases belonging to the body of man are treated of, with excellent methods and receipts for the cure of the same : fitted to the meanest capacity by an index for the explaining of all the hard and unusual words and terms of art derived from the Greek, Latine, or other languages for the benefit of the English reader : with forty copper plates.

THE Description and Use OF THE NERVES.

CHAP. XXI. The first four Pair of Nerves arising within the Skull are described.

THE division or distinction of the Nerves, by reason of their various respects, is wont to be manifold: to wit, as they are either soft or hard, singular or numerous in their be∣ginnings; or that they serve either to the faculty of Sense or Motion, or to both together. But they are commonly distinguished, That some Nerves arising within, the Skull, proceed from the oblong Marrow; and others going out of the joynts of the Vertebra, are derived from the spinal Marrow. But besides these, another manner of differencing them seems best to us; to wit, That some Nerves, as it were Clients and Servants of the Brain, perform only spontaneous Acts, and others, Ministers and Servants of the Cerebel, are imployed only about the exercises of the Involuntary Functi∣on. There will be no need to assign different Effences or Constitutions of Nerves according to these several differences: but rather that there be instituted a particular Cense or Muster of them, and follow∣ing the order of Nature, that we especially unfold every one of them in the series in which they are disposed in the animal Body.

Among the Nerves arising from the Skull, the smelling Nerves, or those which are commonly called the Mammillary Processes, lead the way; for that they have their rise before all the rest, and are stretched out forward beyond the Brain it self. These Nerves go out of the shanks of the oblong Marrow within the chamfered bodies and chambers of the Optick Nerves; and being endued with a manifest cavity, open into the first Ventricle of the Brain on either side behind the same chamfered bodies; so that the humidity flowing between the folding of the Brain, is carried through these chanels into the mammil∣lary Processes; whether they go farther forward, shall be anon inquired into: Because these Nerves being broad and large, arising near the chamsered bodies, and from thence stretched forward under the Basis of the Brain, their bulk is increased by degrees till they go into the round Processes like Paps, by which either bosom of the Cribrous or Sieve-like Bone is besmeared. Within the Socket of this Bone these Nerves, as yet soft and tender, obtain Coats of the Dura Mater; with which being divided into many fibres and filaments, and passing through the holes of the Sieve-like Bone, they go out of the Skull: from whence being dilated or carried forward into the caverns of the Nostrils, and distributed on every side, they are inserted into the Membrane bespreading those Labyrinths.

If we enquire into the nature and use of these parts, without doubt the mammillary Processes and their medullar roots, with the fibres and small threads hanging to the same, are truly Nerves, and serve pro∣perly for the very Organ of the Smell. Seeing these conduce to the sense only without any local mo∣tion, therefore (even as the other hearing Nerve) whilst they are within the Skull, they are plainly me∣dullar and soft; whereby the Animal Spirits more easily moved within the more tender substance of the

Nerves might convey more readily and accurately to the common Sensory the Ideas or Forms of the s•…•…n∣sible Species: But because the Effluvi's or odorous breaths to be received by the naked Organ, carry o•…•…∣tentimes with them sharp and pricking Particles hurtful to the Brain and Nerves; therefore in the first course these Nerves being about to go out of the Skull, borrow Coats from the Dura Mater, which serve for Armour. Further, as these breaths (lest they should strike more sharply by rushing impetu∣ously on the Sensory) being admitted only by little and little, and by small bands, ought to be brought through divers narrow turnings and windings of the Nostrils; therefore that these Nerves may the better receive the effluvia's flowing within the several dens, they are so divided into very many fibres and small threads or filaments, that there may be no passage of the Nostrils to which at least some of them are not destinated. And after this manner, although the exhalations, as it were torn into littleClouds, are received by the nervous filaments, and so care is sufficiently taken, that they being more thickly ele∣vated, may not overwhelm or obscure the Sensory; yet lest any thing sharp and troublesome should be carried with them to the Brain, the cribrous bone is set before the doors as an obstacle, through whose little holes being strained, they may put off all sharpness. And lastly, they being carried through the softer Nerve, as it were another Medium, and so broken again, they at length being soft and gentle enough, are staid at the first Sensory.

But that these Nerves are noted through the whole with an open hollowness within the Skull, the rea∣son seems to be, that the watry humor stilling out of the foldings of the Brain, and being derived into those chanels, might beat back and temper the impressions of the odours, when too sharp and fiery; for as the humors included in the Eye, variously refract the visible Species, whereby it passing at last through the Optick Nerve without any force, slides pleasantly to the common Sensory; so it is not improbable, that the water contained within these passages of the Nerves, does in like manner sweeten the species of the odours, and prepare them in some measure for the Sensory. Wherefore it is observed, that Cattle and Beasts which are fed with herbage, have the mammillary Processes exceeding large and always full of water; to wit, lest the odours of the herbs continually attracted by them (unless their force should be blunted after the aforesaid manner) might hurt or overthrow their more weak brain. Besides, it is very likely that this watry juyce falling down from the insolding of the Brain, doth not only flow into the open chanels of the Nerves and the mammillary Processes, but also doth pass through by the pas∣sage of the fibres and filaments the holes of the Sieve-like bone, and doth wet and continually moisten the cavities of the Nostrils, apt to be dryed or torrified too much by the Air thither attracted, and by the breath continually blown out. For it clearly appears, as we have elsewhere shewn, that the serous humors creep through the blind passages of the Nerves and Fibres, and by them wander from place to place. Yea it may be thought, that not only water, sufficient for the watering the Nostrils, doth by this way sweat through; but also whensoever the serous heap is gathered together in the Ventricles of the Brain, its superfluities or the excrementitious humor doth very often pass through the cribrous Bone by the passage of the Fibres, and is sent out. But we have in another place discoursed more largely of this.

The smelling Nerves, which have within the Skull their mammillary Processes depending on them, are much greater in an Ox, Goat, and in Cattle, and such like beasts that live on herbage, than in flesh-eat∣ing Animals; to wit, because in those there seems to be more need of the sense of smelling to be more exquisite for the knowing the virtues of the manifold herbs. Also these Nerves are larger in all Brutes than in Man: the reason of which is, because they discern things only by the sense, and especially their food by the smell; but Man learns many things by education or nurture and discourse, and is rather led by the taste and sight, than by the smell in chusing his aliments. These Nerves in Birds, as also in Fishes, are conspicuous enough; for either of these, even as four-footed beasts seek out and chuse their food by the help or knowledge of the smell.

As to the Fibres and Filaments or little strings stretching out from the more soft Nerves through the holes of the Sieve-like Bone into the caverns of the Nose, these are found in all Creatures who have the •…•…ammillary Processes: so that it is not to be doubted, but that these Processes, with this Appendix and its medullary origine, is the Organ of the Smell. And what more confirms this thing, these filaments or little strings are far more, and more remarkable in hunting Hounds than in any other Animal whatsoe∣ver. But besides these Nervulets drawn through the holes of the Sieve-like Bone into the Nostrils, two branches also are sent hither from the fifth pair, and distributed into both the Nostrils. The reason of this seems to be, because though the Nerves but now described, or of the first Conjugation, are properly smell∣ing Nerves, and effect by themselves the sense of Smelling; yet these are assisted or joyned with other Nerves, also by those sent from the fifth pair, because the Organ of the Smell ought to have a consent with all other parts, which those subsidiary Nerves, by reason of the manifold branching out of the fifth pair, are wont to perform. It chiefly appears, that there is a certain nearness or strict affinity between the taste and the smell: and the cause of this consists, in that out of the same Trunk of the fifth pair certain Nerves are sent to the Palate, and others to the Nostrils. Concerning the reason of that wonderful consent which the Nostrils have with the Praecordia in sneezing, also wherefore that light titillation stirs up a Cough, shall be spoken of hereafter, when we come to unfold the fifth pair and the intercostal Nerves. But in the mean time we shall take notice, that although many Nerves belong to the Organ of Smelling, yet that sense is properly performed by the Fibres interwoven in the inward Coat of the Nostrils: for those Fibres be∣ing siruck by the sensible object, move and contract themselves variously according to the Idea of the

impression; which Affection of them being carried by the passage of the Nerves to the Head, forasmuch as it is there staid by the common Sensory, causes the perception of the sense. Those sensible Fibres are diversly figured in several Animals; which is the reason, why odorous things do not alike affect all Ani∣mals. For what things by a mans nostrils, as endued with too sharp and pricking Effluvia's, are esteemed highly naught and stinking, as especially are dung and putrid flesh; the same are to Dogs, whose Organ of Smelling is made or consists of more robust or strong Fibres, and proportionate to those Effluvia's, as very grateful and chosen for food.

The second Conjugation are the Optick or seeing Nerves: concerning which we have shewn alrea∣dy, in the Anatomy of the Brain, after what manner they arise from behind the chamfered bodies out of the second section of the medullar shanks (which Galen calls the Chamber of the Optick Nerve) and de∣scending from thence with a certain compass are united, and being again separated and carried into the Ball of the Eyes, constitute with diffused Fibres the hard Coat. Moreover, in those Observations we did but now take notice, that the Trunk of this Nerve growing a little hard without the Skull, was as it were a little bundle of very many Fibres or small strings growing together into one, and of produced Parallels, as it should seem for that end, that the animal Spirits, flowing in the whole Nerve, might be moved in so ma∣ny lines or direct rays; to wit, whereby they may carry the visible Species, sufficiently refracted in the Eye, thence to the common Sensory by a direct beam, and not intorted or rolled about.

As often as in the distempers of the Eyes blackish pricks or concatenated pieces of any thing seem to be rolled before the Eyes, it is likely that this apparition is so made, because certain filaments or small strings of the Optick Nerve are shut up, which when the light cannot pass through rightly, as through the •…•…est, so many as it were shadowy spaces appear in the middle of the clearness. These Nerves, because they only serve for the sense, are therefore more soft within the Skull: but because there may be need perhaps, that the Trunk of this Nerve ought to be sometimes dilated or spread abroad, sometimes bound close to∣gether or contracted according to the divers appearance and incourse of the objects; therefore very many Fibres, being sent out from the motory or moving Nerves of the Eyes, do every where compass and bind it about, and entring with it into the Ball of the Eye, are inserted partly near the root of the Optick Nerve, and partly penetrate more deeply the Sclerotick or hard Coat it self.

Further, the Optick Nerves are not only bound or environed with nervous Fibres sent from the third pair, but (as we have shewn above) with sanguiferous Vessels in their whole process. The office of which certainly is, both that there might be every where about the greater Trunk of this Nerve as it were a continual heat or sufficient fire-place; also perhaps, that the food of the bloody humor might be •…•…up∣plied to the Spirits, living there within the Trunks of the Nerves, far from the fountain, as is wont to be in other places.

Concerning the Fabrick of the Eye it self, and manner of seeing, also concerning the whole dioptrick provision, here seems a fit opportunity of discoursing: but this were to digress too far from our pur∣pose, to wit, the mere or naked Doctrine of the Nerves; and I may the better pass by this addition, be∣cause this Province hath been sufficiently and accurately adorned by others. In the mean time we shall take notice, that as in the smelling, so also in seeing, the sense is performed, not so much by the help of the nerve, as of the fibres, which are interwoven with the organ: to wit, the little fibres in the Membranes of the Eyes, and especially those inserted into the Sclerotick Coat, and disposed after the manner of a Net, do re∣ceive the impression of the visible Species, and by representing the image of the thing, so as it is offered without, causes sight. But it is the office of the Nerve it self to transmit inwardly, as it were by the passage of the Optick Pipe, that image or sensible Species, and to carry it to the common Sen∣sory.

The third Conjugation of Nerves are the moving Nerves of the Eyes, which arise in the Basis of the medullar Stem behind the Tunnel; from whence going forwards nigh the pair of seeing Nerves, and going out of the Skull with the other Nerves destinated to the Eye, they are carried towards the Globe of the Eye; where being presently divided into many branches, they provide it with moving Muscles; but with various difference in divers living Creatures. For in an Ox, who hath got a larger Eye, the mov∣ing Nerve of the Eye imparts a branch to every one of the six common Muscles; and besides, from the Nerves of the fourth, fifth and sixth pair certain branches are distributed to some of the same Muscles: so that, as often as any Animal intends or applies the sense for the perceiving of this or that object, these Nerves turn about the Eye, and compose it at their pleasure for the spontaneous beholding of the same. Besides we take notice, that the Eyes do get a diverse kind of involuntary motion; because in Fear, Shame, Anger, Sadness, yea and in all Affections of the Head and Heart, whether we will or no, the Eyes are re∣spectively figured. Wherefore'tis highly probable, that these kind of pathetick motions of the Eyes, whereof the living Creature is scarce knowing, are performed by the help of the other nerves, to wit, of those com∣ing from the fourth, fifth, and sixth pair: and that more manifestly appears, because the same nerves which lend their branches to the Eye, take their origines from the Cerebel, the office of which we have often shewn to be, to dispense the Spirits for the exercise of the involuntary Function.

But concerning these Nerves of the third pair, which are properly called the Moving nerves of the Eyes, we observe, that in Man, a Dog, and in some other living Creatures they are found to be somewhat otherwise than in an Ox: for either nerve in these, as in the rest, is carried out of the Skull, divided into four branches, three of which are carried from thence into three straight distinct Muscles, to wit, one

lifting up, the other bringing together, the third pressing close the Eye; the other branch of it goes for∣wards further with a single trunk, and is implanted in the middle of the Muscle going about the Eye, turning obliquely to the inward corner downwards. From these it appears, that these Muscles, to which this nerve belongs in all, are sufficient almost of themselves to perform most spontaneous motions of the Eye: but where the aforesaid nerve is divided into four shoots, it constitutes a small and round infolding, out of which many small shoots creep through, and variously compass about the trunk of the Optick nerve; for what use it is so made, we have already intimated.

The fourth Conjugation of Nerves. (which we call rightly the Fourth by order and succession, although it is accounted the eighth and last by Fallopius) hath a diverse origine from all the rest. For whereas most of the others proceed from the foot or sides of the oblong Marrow, this hath its root in the top of it behind the round Protuberances, called Nates and Testes: from whence, bending more forward nigh the sides of the oblong Marrow, it is presently hid under the Dura Mater: under which going along for some space, and passing through the Skull at the same hole with the rest destinated to the Eye, it is bestowed with a single trunk, not communicating with any of the other Nerves, wholly on the Muscle called the Trochlean Muscle. Above we called these Nerves the Pathetick Nerves of the Eyes: for although some be∣sides may deserve this name, (as shall be shewn by and by) yet 'tis most likely, that the proper office of these is to move the Eyes pathetically, according to the force of the Passions and instinct of Nature, deli∣vered and remanded from the Brain to the Cerebel, and so on the contrary, from this to that through the Nates and Testes, and their medullar Processes. For, as we have shewn, that by the diverse impulse and wa∣ving of the animal spirits dwelling in this by-path, there are instituted certain mutual commerces between the Brain and the Praecordia, (the Cerebel mediating between either) it will be of necessity, that these Nerves, rooted in the middle way, should be struck by every tending downwards or remove of the Spirits, going this way or that way, and so the motions of the Eyes to follow the affections of those parts. All perfect Animals are furnished with these nerves: and in truth, as none of them but are obnoxious to Anger, Love, Hatred, and other Affections, so every little Creature shew these by the mere aspect and by the gesture it self of the Eyes. We see sometimes the greater Pike gaping for his prey first of all to roll about his eyes, and to look sour; then with a swift shooting out of his body to invade the lesser fry of fish.

CHAP. XXII. The fifth, sixth, and seventh Pair of Nerves are unfolded.

OF the aforesaid four Pair of Nerves, the two former seem chiefly to serve for the Sense only, but the two latter for Motion; and every single Nerve of them destinated to a peculiar Province: but this which follows next, to wit, the fifth Conjugation of Nerves serves for the exercise of either Faculty, to wit, both of Sense and Motion; nor is its Province so strictly bounded, that it should belong only to one member, for it is distributed to the Eyes, Nose and Palate, and the rest of the parts of the Face, and besides, helps in its part in some sort the offices and actions of the Praecordia and almost of all the Viscera.

This pair (which by the Ancients was accounted the third, by us the fifth pair, and that by right of order or position) below the former nerves, proceeds with a broad and large trunk from the sides of the annular Pro•…•…uberance or Process sent out from the Cerebel. It consists of very many Fibres gathered to∣gether, some of which are soft, others hard; so that the great trunk of it near its beginning, is nothing else than a little bundle of very many nerves, some of which are bestowed on these parts, and others on other parts, and in some they perform the offices of motion, in others of sense. But that so many nerves being de∣stinated to so many several members, and remote one from another, yet arising together, are collected as it were into one bundle, the reason is, that in all the parts to which those Nerves belong, a certain Sympa∣thy and consent of actions might be conserved: to wit, the communion of those Nerves is the cause why the sight and smell move spittle and please the Palate; nor by any other means are the Praecordia affected, according to the various conceptions of the Brain, and transmit their affections to the several parts of the Face; from whence the aspect or countenance of the whole Animal is pathetically figured, as shall be shewed more particularly below.

In the mean time, let us deliver a short Hypotype or Figure of this Nerve; its trunk going out of the sides of the greater Ring, sometimes near its beginning, but oftner the Dura Mater being first perforated or passed through, is divided into two noted branches. The first of these tending straight downward, go∣ing out of the Skull at a proper hole, in its descent towards the lower Jaw, (to whose parts it is chiefly destinated) is divided into more branches, with which it furnishes the Temple-muscle, also the Muscles of the Face and Cheeks. Moreover, from them shoots and branches are distributed

into the Lips, Gums, roots of the Teeth, Jaws, Throat, the farther end of the Palate, yea and the Tongue; for this reason chiefly, that the Nerves going out of the lower branch of the fifth pair, might effect, be∣sides sense, the divers offices of Taste and Touch or Feeling, and motions of a various kind in the afore∣said members and parts; most of which, as the chewing of the aliment, also those which have respect to configuration or framing of the mouth and face in laughing or weeping (as we have already noted) are performed unknown to the Brain, that is involuntarily, and by the help of the Cerebel only, from which these Nerves are derived.

The other superior, and also the greater branch of the fifth pair under the Dura Mater nigh the side of the Turkey Chair goes straight forward for a little space, and is inlarged into some shoots over against the pituitary Glandula to the trunk of the Carotick Artery or the wonderful Net, (where it is present) then it is inoculated into the Nerve of the sixth pair, and from thence sends back sometimes one, some∣times two shoots; which being united with another shoot, turned back from the Nerve of the sixth pair, constitute the root or first trunk of the intercostal Nerve. Concerning this intercostal Nerve, which is made of the lower ramification or branching out of the Nerves of the fifth and sixth pair, it shall be spo∣ken of particularly hereafter.

Presently after the branches or shoots reflected or bent back for the root of the intercostal Nerve, that greater Nerve of the fifth pair is divided into two noted branches. The lesser and uppermost of these tending towards the globe of the Eye, and becoming again twofold, sends forth two branches from it self; one of which turning towards the inward side of the Bone, containing the ball or angle of the Eye, is divided into two shoots. The other of these having passed through the Bone nigh the mammillary Processes, is carried into the nostrils: the office of this Nerve is to keep a Sympathy and consent of action between the Nostrils and some other parts: but the other branch of this division is bestowed on the Muscle by which Brutes wink.

The second Ophthalmick branch of the fifth pair is divided into four or five shoots, all which going forward above the Muscles of the Eye, and in some part passing through its Glandula's, are almost all lost in the Eye-brows, unless that in the passage they send down two small shoots which enter the Scle∣rotick Coat a little below the Tendons of the Muscles, and reach to the Uvea, or the fourth thin Mem∣brane that cloaths the Optick Nerve; yea and also send in the passage small shoots to the Glandula's of the Eye. It seems that these Nerves of the fifth pair, being distributed into the Glandula's of the Eyes and Eye-brows, serve chiefly to the involuntary and pathetick actions of those parts; the chief of which are, the languishing and mournful aspect of the Eyes in weeping, and the unwilling pouring out of tears. For as the lower branching of the fifth pair, to wit, the intercostal nerve, provideth in man for the Praecordia, it easily happens, that from the sad affection of these, the Cardiack branches of this Nerve being forced and wrinkled into Convulsions, the aforesaid Ophthalmick branches also so correspond, and by wrinkling the Eye-brows, and by compressing the Glandula's, produce those kind of looks of the Eyes, and marks of sorrow and grief. Further it is observed, that from the Ophthalmick branch of the fifth pair a certain shoot is sent back higher nigh the heads of the Muscles; which when it has passed through at a proper hole, the Bone containing the ball of the Eye, is carried straight into the caverns of the Nostrils. Hence, as I think, a reason may be given, wherefore passing out of a dark place into the light, at the first beholding of the Sun, presently whether we will or no we shall sneez; to wit, the eyes being too strong∣ly struck by the object, and being suddenly and disorderly moved, that they might turn themselves aside, the same affection is immediately communicated through the aforesaid Nerve to the Membrane covering the hol∣low caverns of the Nostrils, which being thence contracted and wrinkled, (as it is wont by some sharp thing pulling it) provokes sneezing.

The second or greater branch of the second division of the Nerve of the fifth pair being carried nigh the ball of the Eye, is again divided into two branches. The lower of these being bent downwards, cleaving into many shoots, is bestowed on the Palate and upper Region of the Jaws: The other and higher branch of this second division stretching beyond the ball of the Eye, passes through, together with the Vein and Artery, a proper hole made in the bone of the upper Jaw; which Vessels this Nerve climbs and variously compasses about with many shoots sent forth; then arising out of the bone, it imparts little branches to the Muscles of the Cheeks, Lips, Nose, and to the roots of the upper Teeth. Therefore forasmuch as this Nerve embraces and binds about the sanguiferous Vessels destinated to the Cheeks and the other parts of the Face; from hence a reason may be given, why the face is covered with blushing by shame: for the ani∣mal Spirits being disturbed by the imagination of an unseemly thing, by and by endeavouring as it were to hide the face, their irregularities enter this Nerve, so that the shoots of the same Nerve, embracing the blood-carrying Vessels, by compressing and pulling the same, cause the blood to be more forced into the Cheeks and Face, and the Veins being bound hard to be there for some time staid and detained. But for∣asmuch as many shoots and fibres of the same maxillar Nerve, derived from the fifth pair, interweave themselves with the flesh and skin of the Lips, hence the reason is plain, why these parts are so very sen∣sible, and besides, why the mutual kisses of Lovers, impressed on the Lips, so easily irritate love and lust by affecting both the Praecordia and Genitals; to wit, because the lower branching of the same fifth pair actuates these parts constituted in the middle and lower Belly, and draws them into the like affection with the Lips. The same reason holds of Love presently admitted by the eyes, that as the Poet says,

Mars videt hanc, visam{que} cupit. As soon as Mars saw her, he desir'd her.

We have but now intimated, that many shoots os this Nerve were destinated for the business of chew∣ing; and therefore, because the aliments to be taken ought to undergo not only the examination of the taste, but also of the smell and sight, from the same Nerve, whose branches being sent to the Palate and Jaws, perform the business of chewing, other shoots, as it were fore-runners, are carried to the Nostrils and Eyes, to wit, that these Organs of the other Senses might be furnished with some helps of proba∣tion also, for the better knowing or distinguishing the objects of taste. Certainly from the nearness of kindred and manifold affinity of this Nerve, being also much diffused in the Head, the mutual de∣pendencies and confederations of very many of its parts, proceed. But how this Nerve in other Pro∣vinces, to wit, in the Thorax and lower belly, and there about the motions and sensions of the Prae∣cordia and Viscera, doth cause various Sympathies of them among themselves and with other parts, shall afterwards be more largely shewn, when we shall speak particularly of the intercostal Nerve, which is rooted in this Nerve of the fifth pair; where, from the manifold communication of this Nerve, may be easily drawn the reasons of sneezing, yawning, laughing, crying, and of other acti∣ons merely natural. In the mean time, the superior branching of the Nerve of the fifth pair shews it self after this manner in the Head, and almost after the same manner is divaricated in most liv∣ing Creatures; except however, that in some presently after its rise, it is divided into three great branches; one of which is destinated to the lower Jaw, the other to the Eye and Nose, and the third to the Cheek.

The Nerve of the sixth Conjugation follows, which arising out of the lowest foot of the annular Protuberance, and being hid under the Dura Mater: presently goes out of the Skull at the same hole with the nerves of the third and fourth pair, and is carried with a single Trunk into the ball of the Eye; but so, that near the side of the Turkey Chair it is inoculated with the second branch, or the greater of the fifth pair; from whence it turns back, sometimes one little branch, sometimes two; which being united with the branches of the fifth pair running back, constitute the beginning of the intercostal nerve. Then this nerve going forwards, is divided into two branches near the ball of the Eye; one of which is inserted into the Muscle drawing back the Eye planted in its outward angle; and the other being torn into various fibres, is bestowed on the seventh Muscle pro∣per to Brutes; so that this nerve also seems to serve to those motions of the Eye that are almost on∣ly pathetick, or excited by natural Instinct. For, as to the use of the former shoot, it plainly ap∣pears, that it is innate to every Animal in a sudden fear to draw the eyes backward, and to look for what is to be feared on either side and behind: then as to its other shoot, whereby Brutes winke or twinkle the eye, it is obvious that this same motion is sudden and extemporary, without any previous intention, whereby the eye endeavours to shun the injuries of outward things that occur.

The seventh Conjugation of Nerves, accounted for the fifth by the Ancients, is imployed about the sense of hearing. Of this pair commonly are noted two Processes, the one soft, the other hard; which indeed seem to be two distinct nerves, for that although they have their beginnings nigh one another, yet are somewhat distinct, and are carried to divers Organs; in the mean time either agree∣ing in a certain common respect of use or action. For whilst one Nerve performs the act of hearing, the other supplies some requisites whereby that act may be the better performed: wherefore we shall not much strive against the common description of this pair, by which it is taken for one. The process of this pair, or the auditory Nerve properly, which is called the soft Branch, seems to arise in man out of the lower side of the ringy Protuberance, and in beasts out of the midst of the lesser Ring. In some Diffections I plainly found, that this softer Nerve, having its beginning lower, seem∣ed to ascend a little before it went out of the medullar stock; and the other more hard Nerve seem∣ing to arise higher (viz. out of the medullar whitish line leading about the bottom of the fourth Ventricle) did descend a little, and arose near the meeting with the other. This softer Nerve is car∣ried into the passage of the stony Bone, where entring into the den destinated for the receiving the sound, which is on this side the Snail-like winding and the Drum, it so infolds it self into the most thin Membrane wherewith that den is covered, that as often as the Air implanted in that cavern is moved by the stroke of the external Air made upon the Drum, this impression striking this Membrane, and stir∣ring up as it were an undulation of the animal Spirits, is forthwith carried towards the common Senso∣ry by the passage of the Nerve there implanted. There will be a more opportune place of discoursing, after what manner, and by what sort of Organs Hearing is performed, when we shall speak of the Sen∣ses.

The other Nerve of this pair, or the more hard process, which conduces rather to motion than sense, passing through the stony Bone at an hole proper to it self, arises near the auditory passage, where it pre∣sently receives into its trunk a branch from the wandring pair brought thither; then immediately after that joyning together or coalition, it is divided into two branches: The first of these tending down∣wards, is bestowed upon the Muscles of the Tongue and the Bone Hyoides; the other going about the au∣ditory passage, and bending more upwards, is divided into three shoots; the first of which, answering to the Nerve of the former division, bestows some shoots on the Muscles of the Lips, Mouth, Face, and Nostrils, and so actuates some exterior Organs for the forming the voice, as the former doth some inte∣rior Organs. The second shoot of this division distributes its shoots into the Muscles of the Eyebrows

and Forehead; and the third into the Muscles of the Ear it self. The offices and uses of all these have been already shewn, the summ of which is, that as often as the sound is admitted in, especially if it be any ways unusual, new, or to be wondred at, presently by a certain natural instinct the Ears and Eyes erect and open themselves: to wit, for that end shoots from this Nerve are inserted into the Muscles of the Eye-lids and Ears, that by the passage of these, the Spirits inhabiting either Region, might be call∣ed out as it were to watch. For a like reason shoots from the same hard process of this Nerve are di∣stributed both into the Muscles of the Tongue and of the Bone Hyoides: as also into those of the Lips and the outward parts of the Mouth, that by their passage, the sound being transmitted further to these Organs of the voice, it being equal or like the same, might officiously answer it as it were an Echo. That the descriptions of the aforesaid Nerves might be better understood, I have thought good here to represent in the following Figure the branchings of the fifth and sixth pair. The seventh pair is fitly deli∣neated in the ninth Figure.

This Figure shews the Branchings of the fifth and fixth pair of Nerves.

• A. The Nerve of the sixth pair (which we place first, because it is outmost in the Scheme) from whose trunk two shoots a. a. are carried into the two Muscles of the Eye.
• A. A shoot from the Nerve of the sixth pair bent back for the root of the intercostal Nerve.
• B. The trunk of the fifth pair being presently divided into two great branches.
• bb. Two shoots from this branch bent back for the root of the intercostal Nerve.
• C. The division of the upper part of the trunk into four lesser branches, the uppermost of which c. being the Ophthalmick or belonging to the Eye, and entring the orb of the Eye, sends forth four shoots.
• c. The first being carried nigh to the ball of the Eye, is bent back into the Nostrils.
• d. The second passing by the outward orb of the Eye, is carried into the Muscles of the Forehead.
• ee. The third and fourth are distributed into the Eye-lids and interior Glandula's of the Eye.
• D. The second branch of the second division is also Ophthalmick, which entring the ball of the Eye, and carried towards the outward corner of the Eye, is distributed into the Eye-lids and outward Kernels.
• E. The third branch of the second division, or the maxillar, which passing by the orb of the Eye, enters and hole proper to the bone of the Jaw, in which passage it sends forth a shoot e. through another hole into the chew∣ing Muscle, then arising up, it is carried out at the hole.
• f. A shoot into the Muscles of the Nose.
• ggg. It sends fortb many shoots into the upper Lip.
• F. The lower branch or the fourth of the second division, which descending right towards the hollowness of the Mouth, is divided into two branches.
• h. The first is distributed into the Gums.
• i. The second is bestowed with many shoots upon the Palate.
• G. The second branch of the first division of the fifth pair, which tending straight downwards towards the lower Jaw, sends forth in its passage many shoots.
• k. A shoot of it into the Parotid Glandula's, or those near the Jaws.
• l. A shoot to the inward Mandible.
• m. A shoot which compassing about the process of the lower Jaws, is carried to the outward part of the exte∣rior Masticator.
• n. Another shoot tending opposite to the former, having compassed the same process is distributed into the inward part of the same Masticator.
• H. The trunk of the same greater branch carried further, is cleft into many shoots, of which
• o. Tends into the root of the Tongue.
• pp. Is carried with many shoots into the substance of the whole Tongue.
• q. Into the parts under the Tongue.
• r. Passing through the bone of the Jaw, is divided into many shoots which are dispersed, partly into the lower Lip s. s. s. and partly into the Chin t. t. t.

[illustration]

Fig. I.

[illustration]

Fig. II.

KK. p. 118

The Second Figure shews all the Nerves, which being carried from the Nerves of the third, fourth, fifth, and sixth Pair, are bestowed upon the Muscles and other parts of the Eye.

• A. The Nerve of the third pair carried to the three straight Muscles, and into the outward oblique one.
• B. The Nerve of the fifth pair, or the pathetick Nerve, goes whole into the trochlear Muscle.
• C. The Nerve of the sixth pair into the drawing back Muscle, and the seventh proper to Beasts.
• D. The Nerve of the fifth pair whose Ophthalmick branch E. is divided into two branches,
• F. The upper branch, being presently torn into manyshoots, tends directly towards the inner corner, where it is bestowed on the Glandula's and Eye-lids.
• G. The lower Ophthalmick branch, which being divided into shoots, respects after a like manner the Glandula's and Eye-lids towards the outward corner of the Eye;
• a. The Nerve of the fourth pair for the trochlear Muscle.
• b. A branch of the Nerve of the third pair for the Muscle lifting up the Eye-lids.
• c. A branch of the same pair for the Muscle shutting the Eye-lids.
• d. A branch of the same Nerve for the Muscle pressing close the Eye-lid.
• f. A branch of the same for the outward oblique Muscle.
• g. Lesser Nerves out of the infolding of the third pair, tending through the Sclerotick Coat into the Uvea.
• e. The Nerve of the sixth pair for the drawing-back Muscle.
• *** Fibres or lesser branches from the fifth and sixth pair for the seventh Muscle, proper to Brutes.
• h. A Nerve coming from the upper Ophthalmick branch into the Nostrils.
• i. A Nerve from the same branch into the Eye-brows and Fore-head.
• H. The trunk of the fifth pair cut off, which tends to the lower Jaw.
• I. A branch of the same cut off, which is carried to the Palate.
• K. Its upper maxillar branch.

CHAP. XXIII. The Description of the eighth Pair of Nerves.

THE Conjugation of the Nerves of the eighth pair, accounted by the Ancients for the sixth, is cal∣led the Wandring pair; to wit, for that its Nerve, not content with one member or region of the Body, is thought to respect divers parts, and those different, and situate at a great distance one from another, and to reach forth its branchings, not only in the neighbourhood about the Head and Neck, but through the whole cavity of the middle and lowest Belly, and to most of the Bowels in ei∣ther. But indeed this nerve hath a province large enough, yet not so diffuse as is commonly thought: for many other nerves, inoculated into this, joyn themselves with it, and are accounted a part of it, although they have distinct beginnings, and going away again from the nerve of the eighth pair, have peculiar diva∣rications, and different from it. Wherefore, that we may give to each its own, we shall endeavour to pro∣secute this nerve of the wandring pair from the beginning to the end; and also shew the confederations and coincidences or joynings together of others with it.

The eighth Conjugation therefore of the Nerves arises below the auditory or hearing nerves out of the sides of the oblong Marrow, its root consisting of numerous Fibres. In a man thereare at least twelve, some of which are greater, others smaller; to which is added a noted Fibre, or rather Nerve, much great∣er than the rest, from the spinal Marrow, which being joyned with them, and wrapped about with the same Coat, taken from the Dura Mater, goes forth together out of the Skull, as if they all grew into one Trunk: but that accessory nerve, yea and many other Fibres, do still remain distinct under that covering and afterwards departing asunder, are carried into peculiar provinces.

Because this spinal Nerve having passed the Skull, leaving its Conjugation, is carried to the muscles of the Neck and Shoulders; besides, the noted Fibre, out of the beginning of the wandring pair, is present∣ly carried into the hard process of seventh Conjugation; and two other Fibres, having presently left the company of the rest, go into the muscles of the Throat and Neck: but the rest of the Fibres, being collect∣ed together, go forward still as Companions, and instead of their other Companions which departed srom them, they presently get new in their places; to wit, sometimes the whole trunk of the intercostal nerve it self, as is seen in most four-footed Beasts, sometimes only a branch of it comes to them, as is ob∣served in Man and some other living Creatures.

In this place where the trunk or branch of the intercostal Nerve is inoculated into the trunk of the wandring pair, a noted infolding is constituted, to wit, the trunk of the nerve being there made greater, seems to be lifted up, and to grow out into a certain Tumor like to a callous or sinewy-swelled body: here, for that it is somewhat long, it is called by Fallopius the Olive body; of which sort the same Au∣thor affirms, there comes to this nerve sometimes one, sometimes two; but in truth, one is constantly found in the trunk of the wandring pair, but the other in the neighbouring intercostal.

Of these sort of infoldings in general we shall take notice, that they are made in the Nerves, as joynts in a Cane, or knots in the stem of a Tree, viz. as often as a branch goes out of the trunk, or sliding into another place, is received into the same; and whem oftentimes some shoots go away from the place, and others come to it, the infolding there becomes greater; and so the more branches and shoots do happen to come together any where, or to go out of a nerve, the greater the bulk and magnitude of the in folding is increased: but if at any time a branch seems to proceed from any nerve without constituting an infolding, in truth, being included only in the same Coat, it is not accounted so much a branch as a companion which by a passage long before, had gone together forwards, as a single nerve it self, and distinct enough nor was it at all inoculated before its departure. But the use of these same infoldings seems to be the same with the knots in the stem of a Tree, or such as the turnings aside or by-paths that lye near cross-ways; to wit, that when the animal Spirits, together with the nervous Juyce, institute divers journies, lest mutually, meeting, they should be confounded, they may be able to turn aside a little, and depart one from another till they may recover their orders and just method.

In the Dessection of the Nerves, which are distributed to the Praecordia and Viscera, the two Ganglioform infoldings, to wit, the aforesaid in the trunk of the wandring pair, and the other near growing in the intercostal nerve, are as it were two bounding stones, which being first diligenly traced, the other threads of the Anatomical task, both on this and that side, are easily handled. But that these infoldings may be found, the trunk of the Carotidick Artery is laid open on both sides between the Muscles of the Neck; then by following its tract, the aforesaid Olive bodies come into view about the insertion of the lower Mandi∣ble; out of which, both the upper beginnings and the lower branchings of either nerve, may be de∣signed or drawn. But because about this place the nerves begin to be figured otherwise in a Man than in Brutes; that the reason of the difference may be known, we will here prosecute apart and distinctly the Neurologie or Doctrine of the Nerves of either, and first we shall deliver the Hypothesis of the wandring pair, and its consederations with the intercostal and other nerves, as they are found in Man.

The Ganglioform infolding therefore being constituted upon the Trunk of the wandring pair, receives one Nerve sent into it elsewhere, and sends forth another from it self. To this is brought a shoot from the intercostal nerve different from most brute beasts, where the whole trunk of the intercostal nerve comes, and seems to be united to the wandring pair. But from the aforesaid infolding, a noted branch being sent forth, is carried towards the Larynx, which when it is divided into three shoots, the first of them is stretched out into the Sphincter of the Throat; the second being hid under the Scutiform or Shield-like Cartilage, distributes its shoots to the upper Muscles of the Larynx, and to the Muscles by which the chink of the Larnyx is shut up; and the third also entring the Shield-like Cartilage, meets the top of the returning nerve, and is united to the same. Such an inoculating of this nerve, with the returning nerve, is constantly found in man and in all other perfect Animals; the reason of which is delivered anon.

Below the aforesaid infolding of the wandring pair, its stem, near the side of the ascending Caroditick Artery, goes forward straight downwards, and in its journey imparts some small shoots to the same, which sometimes compass about the trunk of its Vessel, sometimes are inserted into its Coats. In the lower par of the Neck this trunk of the wandring pair admits a branch of the intercostal nerve from its neighbour∣ing infolding, and in the left side about that place sends forth another nerve from it self into the re∣turning nerve, which cross branch, being stretched out only in the left side, is found in man and all brute beasts: but from thence the trunk of the wandring pair descends without any noted branchings till it comes over against the first or second Rib; where another infolding being made, many shoots and nu∣merous fibres are sent forth towards the Heart and its Appendix. But this divarication of the Cardiack nerves is not after the same manner altogether in either.

For in the left side one or two noted shoots being sent forth, together with the other shoots arising from the intercostal Nerve, are inserted into the Cardiack infolding; but many fibres going out at the same place, are distributed to the Vessels hanging to the Heart, and to its little Ears and Pericardium. In the right side a noted shoot going into the greater Cardiack infolding, another into the less, and two other shoots from the middle infolding of the intercostal Trunk towards the Cardiack infolding, associate them∣selves and are united. Besides, numerous Fibres in like manner descend into the Vessels of the Heart and the Pericardium. Also the returning Nerve in this side arising higher, is turned back about the axillary Artery, when in the left side the same going away much lower than this infolding from the Trunk of the wandring pair, compasses about the descending Trunk of the Aorta, and from thence it is turned back upwards.

The returning Nerve, although it seems a branch sent forth from the Trunk of the wandring pair, being indeed a distinct and singular nerve, comes even from the beginning of wandring pair; yet for bet∣ter conducts sake it is contained under the same Coat with the rest of the Trunk of the wandring pair. In either side about the knots of reflection or turning back, it sends forth shoots and fibres which are di∣stributed into the Vessels of the Heart. The reflected Nerve in its ascent receives in the left side a branch from the middle infolding of the Intercostal, and another from the wandring pair, but either running back, distributes many shoots to the rough Artery; then its extremity meeting with the shoot, which is sent out of the Ganglioform infolding of the wandring pair, is united to it.

A little below the coming away of the returning Nerve on the left side from the Trunk of the wandring pair, another noted branch is sent forth on both sides; which being carried towards the Heart, covering its Basis in the hinder Region, meets it on both sides, and disperses in all its process branches through the whole Superficies of the Heart. As shoots go from these branches into the hinder part of the Heart, so ma∣ny branches and shoots go from the Cardiack infoldings which are divaricated into its fore-part.

But there are two infoldings from which the Nerves are distributed into the Heart, The upper and greater is between the Aorta and the Pneumonick Artery. The nerves constituting this are one or two noted branches that descend hither from either side the Trunk of the wandring pair; but chiefly many nerves form either intercostal nerve, to wit, from the midst of its infolding. From this infolding two or three noted nerves are carried under the Aorta into the left side of the Heart. But from this infolding a shoot being sent forth, making as it were an handle, compasses about the pneumonick Artery; and a branch descending from the right Trunk of the wandring pair to the exterior part of this handle, and another, which being carried from the nerve which is destinated to the hinder region of the Heart, meet together and make the lesser infolding; from which nerves are sent into the right side of the fore-part of the Heart.

We are to take notice, That in brute Animals many more and far greater Nerves are carried from the Trunk of the wandring pair into the Heart and its Appendix than in Man, to wit, in whom the chief Cardiack nerves or belonging to the Heart proceed from the intercostal pair, as is shewed below; where∣fore in Brutes, for that reason, the wandring pair affords greater supplies or subsidies to the Heart, because the intercostal nerve searcely contributes any to it. Further, through the whole tract of the wandring pair, from whence the Cardiack nerves proceed, very many small shoots, being sent forth on both sides, are in∣serted into the Oesophagus and the Glandula's implanted without the Pericardium.

From the Region of the Heart, the Trunk of the wandring pair sends forth many noted shoots on both sides, which being carried into the Lungs, are distributed, together with the blood-carrying Vesses, through their whole substance, and in their passage step by step they follow the Pipes of the Bronchia, both the Arteries and the Veins, and many shoots being sent forth on every side, they climb upon and compass about these Vessels; then the Trunk of the same wandring pair, descending on both sides, nigh the sides of the Trachea, distributes many shoots also into the Coats of the Oesophagus.

Below the Pneumonick branches, either Trunk of the wandring pair going forwards downwards nigh the sides of the Oesophagus, is divided into two branches, viz. into the exterior or more outward, and the interior or more inward. Both the inward branches inclining towards one another mutually, do again grow into the same Nerve, which being sent straight down towards the Oesophagus, and being carried nigh the inward part of its Orifice, is bent back from thence, and creeps through its upper part. From both branchs, being carried nigh the opposite parts of the superior Orifice, many shoots are produced, which being mutually inoculated, do constitute the nerves infolding like a little net. The Stomachical lower branch sends forth very many fibres and shoots nigh the left part of the bottom of the Ventricle, which are united with others, sent forth from the Mesenterick and Splenetick infolding. Further, in the right part of the same bottom of the Ventricle, shoots being sent forth from either Stomachical branch, are united with other shoots sent upwards from the Hepatick infolding; and about this place either Trunk of the Nerves of the eighth pair seems to be terminated, for that the last that may be perceived of it are some shoots sent forth from the Stomachical branches, which are inoculated or ingraffed with the little branches or fibres sent upwards from the Mesenterick infoldings.

CHAP. XXIV. The Actions and Uses of the Nerver of the eighth Pair, described in the fore∣going Chapter, are unfolded.

AFter this manner the beginning and branchings out of the Nerves of the eighth pair are disposed in Man: and they are almost after the same manner in Brutes, unless the Cardiack branches be more, because in these they go out only from this one Conjugation. The Figure or Type of all these is well designed or drawn in the ninth Table or Figure, It now remains, recollecting the Tracts of this Descritption, or at least the things chiefly to be noted, that we inquire into the Rea∣sons of their Phenomena or Appearances.

This Nerve, presently after its rise, appears with numerous Fibres, as may be discerned in the ninth Figure E: the reason of which is because many nerves here arising together, and deriving plenty of ani∣mal Spirits from the same stock or provision, ought to carry the same to divers parts, and remote one from another; and therefore they assume their Latex or Juyce, not at one Trunk, as the blood carrying Ves∣sels, and afterwards distribute it equally by branches and shoots here and there stretched out; because the Spirits, derived from the same Fountain, have need to flow into these parts separate from them, and vari∣ously to transpose and change their influence: wherefore for this business it is required (that we may not suppose little doors in the middle of the branchings out of the nerves, as are in the Pipes of a musical Or∣gan) that the nerves, which are destinated for the performing of divers offices respectively in distinct parts, should be single in their whole passage, and of themselves distinct chanels of Spirits; for the sake of a better conduct many of them are collected together, and seem to grow together into one Trunk; but they are parted both in their beginning, and also in their whole journey, and distinguished, though involved in the same Coat, and so are carried to the respective parts. Otherwise how should it come to pass, that the Spirits to be carried for the performing the instinct of motion towards the Stomach, do not enter at the same time the Lungs or 〈◊〉〈◊〉, and actuate them with an inordinate influence? For indeed the shoots of the nerves of the wandring pair may be followed by the eyes and band backwards towards the beginning, from the parts into which they are inserted, and where they seem to be united into the same Trunks so separated with the finger, that it may appear they are single. After the fame manner we have plainly separated one from another the returning nerve also, and others, their common Coat being dis∣sected. Yet in the mean time we deny not, that in their progress they do communicate one with ano∣ther by Fibres meeting mutually, if it be granted, that the fame, although they arise together, in their very rise it self are in a manner distinct. For by reason of the nearness of the beginning and progress, though all the nerves of the wandring pair have a certain Sympathy and consent in their actions; yet for that they consist of parted strings, they perform their actions successively, and convey the influences of the Spirits to these parts separate from those.

We have already shewn, that the Nerve of the wandring pair, and others belonging to its family, do serve almost only to the involuntary Function. Wherefore it may be thought, that as there are many shoots and fibres, which going out distinctly from the same origine, are carried to divers parts, that Indeed those Bowels and Members, into which these nerves are inserted, do perform their particular actions, stirred up either by the instinct of Nature, or by the force of the Passions, the Animal in the mean time scarce knowing it: yea also, that when certain other nerves, arising afar off, are joyned to this Tru•…•… of the wandring pair, and communicate with it near the very origine of it; this seems to be therefore done, that those nerves, an affinity with the wandring pair being begun, may be drawn into Sympathy with it, and into an unity of action of the involuntary Function. This appears clearly by the accessory nerve from the Back-bone, and some others, as shall be manifested anon.

In the mean time, we shall observe concerning the Fibres of the wandring pair, first that a noted shoot, inclining towards the vocal process of the seventh pair, is united with the same, as in the ninth Figure e. Hence a reason may be taken, wherefore in every violent Passion, as of Anger, Fear, Joy, and the like, without the will or intention of the Animal, the Tongue sends forth a voice, as an index of the excited affection; so that not only men, but some brute beasts, in their fleeing or rejoycing, wail, cry out, and make a noise.

Secondly, from the beginning of the wandring pair very many Fibres are distributed into the Muscles of the Neck, Figure the ninth FFF. in which there seems little need of the stirring up of spontaneous motions in that part; for to this task the Vertebral nerves servo sufficiently. Notwithstanding the afore∣said Fibres of the wandring pair are the cause why the Neck is moved about in fear, or at any noise or sus∣picion of danger; and also, why in some Animals, from indignation or pride, the Muscles into which these nerves are inserted, being inflated very much, their necks swell up, and the Crests of many are erected. Of how great use the accessory nerve, coming from the Spine to the wandring pair, is for the pathetick mo∣tions of the 〈◊◊◊◊〉〈◊◊◊◊〉 presently.

Thirdly, The other Fibres of the wandring pair, being gathered togather, seem to grow together into the same Trunk, which presently constitutes the Ganglio form infolding from a shoot coming from the intercostal nerve, as in Figure the ninth G. H. And indeed it is very likely, that of these Fibres, which are complicated together in the Trunk of the wandring pair, one is destinated to the returning nerve, another to the Precordia, a third to the Lungs, and lastly, another to the Ventricle; all which, al∣though they have communication among themselves, and for the sake of a better conduct are gathered together in one, yet they are still distinct from their very original, and constitute divers passages of the animal Spirits.

But that a shoot is carried from the intercostal Nerve into the upper infolding of the wandring pair, as in the ninth Figure h; the reason is, that between these nerves a certain strict affinity and kindred might be, and that either of them might be affected with the others offices. For as the nerve of the wan∣dring pair distributes shoots chiefly to the Praecordia, and the Stomach, and the intercostal Nerve to the rest of the Viscera of the lower Belly; we may observe, that between all these there are not only some com∣merces, but Sympathies, and a consent of Actions and Passions; wherefore there is a necessity, that the nerves designed to either parts, should communicate among themselves. Further, in Man the intercostal nerve imparts to the Heart and its Appendix more shoots and fibres than the nerve of the wandring pair: wherefore these nerves, do not only communicate by these superiour infoldings, but also again alittle lower by a shoot sent out from the cervical infolding, or that of the Neck.

From the aforesaid infolding a noted branch of the wandring pair is sent forth into the Muscles of the Larynx, a certain branch of which, entring the Shield-like Cartilage, meets with the returning nerve, and is united to it Fig. 9. h. It will not be difficult to collect what the use of this nerve may be; for seeing the Larynx or the rough Artery serves both for the drawing in and putting out of the breath, and also for the modulating the voice, for either office that its Trunk, like the folds in a pair of Bellows, may become sometimes more short, sometimes more at length, these same ringy Cartilages ought to be pulled toge∣ther, or contracted sometimes upward, and sometimes downward. That a flat voice or sound might be formed, they ought to be prest down as much as may be to the bottom; but if you would form a more shrill or sharp sound or voice, the superiour Rings are lifted up; to wit, that the sound might be broken but only in the very passage of the Jaws. For the performing of this double motion of the Larynx two nerves are constituted like the hands of a Piper, one of which stops the lower holes, the other the upper of the Pipe: to wit, the shoots and branches of the returning nerve being lifted up from below, move the ringy Cartilages downwards; and the nerve sent out from above from this infolding, presently draws the more superior upwards. Further, because a certain consent and joynt action is required in both nerves, therefore they are mutually inoculated or ingraffed: yea, whenas either of them returning, distributes fre∣quent shoots into either side of the Trachea; it seems that those that are sent out into the right part, move its Rings downwards for Inspiration and a strong Voice; and the others, going out on both sides into the left part, carry the Rings upward for Expiration and for an acute or sharp Voice. Moreover, as the instinct for the motion of depression or pressing down is delivered from the knots of the recourse or re∣flections; so the impression, for the elation or lifting up of those parts, is received from this nerve of the Ganglioform infolding.

A noted branch from the middle infolding of the intercostal Nerve is carried into the Trunk of the wandring pair, Fig. 9. i. For what end that is so, we have shewn already; to wit, that the commerces of the Spirits dwelling in both nerves, might be strengthened: but it should be noted, that it is only so in the left side where the Trunk of the wandring pair shews it self single for a long space; but in the right side, where the returning nerve goes from it much higher, here the other nerve from the intercostal infolding is plainly wanting.

About the Region of the first or second Rib, another noted infolding appears in the Trunk of the wandring pair, from which many shoots and fibres are sent towards the Heart and its Appendix, Fig. 9. k. Further, in brute Animals, about this place, the intercostal nerve leaves the Trunk of the wandring pair. Without doubt, some animal Spirits go apart in this infolding, which are destinated to the anterior region of the Heart, also to the Pericardium and some of its Vessels, whilst other Spirits pass through, which a lit∣tle lower are derived into the hinder region of the Heart; and which being yet carried further, go to the Lungs, and lastly to the Ventricle.

We may observe, that from the aforesaid infolding of the wandring pair numerous shoots and fibxes are sent forth, which are distributed into the little ears of the Heart and all the sanguiferous Vessels be∣longing to the Heart, Fig. 9. l. m. which fibres and nervous shoots creeping along like Ivy, thickly cover over the Coats of the Vessels, and enter them in very many places, and variously bind them about. Truly this copious distribution of the nerves doth effect the pulsifick force in the little ears of the Heart and in the Arteries, or at least seems to excite it; and so to erect and strengthen those parts by a continual influx of the animal Spirits through these nerves, that they may be able to sustain an undiscontinued reciprocation of Systole and Diastole. Moreover, that the thick fibres and shoots of the nerves are inserted both into the Veins and Arteries, and bind both those kind of Vessels, and variously compass them about, we may lawfully suppose, that these nerves, as it were Reins put upon these blood-carrying Vessels, do some∣times dilate, and sometimes bind them hard together for the determining the motion of the Blood

according to the various force of the Passions, or to deduce it here and there after a manifold manner; for by this means it comes to pass, that in fear the excursion of the blood is hindred, and in other Affec∣tions its motion is respectively altered.

But that many shoots and branches are inserted into the Pericardium, it seems to be for this use; to wit, that that little Chest which is made like a Fort for the defending the Heart from injuries, as often as any throublesom matter assaults or besieges it, might be able to draw it self together, and to shake off the enemy. For it seems, that the inordinate tremblings and shakings of the Heart, which are manifestly dif∣ferent from its natural Pulse, proceed from the violent shaking of this Membrane.

As to the Cardiack branches sent from this infolding, we observe, that they, because destinated to a publick office, do therefore communicate and enter into the pairs of either side before they are inserted in∣to the Heart; for which end the infolding is made before the Basis of the Heart, where the aforesaid shoots from the wandring pair and many others, going out from either intercostal nerve, meet together. From that infolding, placed betweem the Aorta and the pneumonick Artery, very many branches being sent forth above, cover over the Hemisphere of the Heart: but yet from these certain branches, carried un∣der the Aorta, are brought into the left side of the said Hemisphere; and as other pairs tend towards the right side, one of the first of them, making a little handle, binds about the pneumonick Artery; then meet∣ing with other Cardiack shoots, makes the lesser infolding, out of which branches are sent forth into the right and anterior side of the Heart. That from the greater Cardiack infolding, nerves departing one from another, do institute contrary journies towards the Heart, it is indeed, that they might come to divers regions of the Heart without meeting one another, and might affect its Vessels respectively in their passage; to wit, the branches carried this way, insert their shoots into the Aorta, and from the others go∣ing that way, one compasses about the pneumonick Artery. The reason of both seems to be, that the blood might be either sooner or slower drawn from the bosoms of the Heart for its various need or ne∣cessity. For whilst the aforesaid nerves do both sustain its motion by their influx, and also moderate and temper it by their instinct, it so comes to pass from thence, that those Vessels also, being affected by the same nerves, do further compose themselves to the requisite Analogies and proportions of the Pulses.

Indeed there are many Nerves, and those conspicuous enough, which are inserted into the Heart, and cover its outward substance with shoots sent forth from all sides; yet it is not to be thought, that these nerves alone perform and sustain the undiscontinued motion of the Heart: because so small little ropes seem too unequal for the perpetual agitation of such a Machine. Yea it may be observed, that more shoots and fibres of nerves are distributed into the little ears of the Heart and the depending Vessels, than into its frame or substance. Further, it is obvious to any that will behold it, that there is a greater plenty of nerves destinated to the Lungs, Liver, Spleen, Ventricle, or Reins, than to the Heart it self; so that some Anatomists (a Fallopius says) were doubtful, whether there were any nerves that belonged to the Heart or not. But this being clear enough, that we may describe the motive power of this Clock or Machine stirred up by the help of some small nerves, as it were an explosive motion, we say that the substance of the Heart it self consists of a very fibrous flesh, and may rather be called a Muscle than Parenchyma or congealed substance: wherefore in this, as in other Muscles, the implanted and proper fibres cause the local motion and constant shaking; but by the inserted nerves is only conveyed the instinct of the motion or action; for the performing of which office, both fewer Nerves and fewer animal Spirits flowing in through their passages, do suffice. But indeed we suppose, that the animal Spirits implanted in the Heart, and abiding within its Fibres, did at first flow thither through the nerves, and that by this way their expences or loss are made up or supplied; yet that the animal Spirits, which seem to be dispensed to the Heart by so spa∣ring an hand, may suffice for the actuating this perpetual motion, they receive continually subsidiary Forces from the arterious blood. For elsewhere we have shewed, that in the Heart, as in the whole musculous stock besides, a sulphureous Copula, from the suggested blood, is joyned to the spirituous saline Particles of the implanted Spirits; which matter, whilst the Spirits are agitated, being at length struck off, and as it were exploded (just like the rarified and in kindled Particles of Gun-powder) for the effecting the mo∣tive endeavour, do blow up or intumifie the Muscle or the Heart it self; and so from the indiscontinued action of the Heart much of this sulphureous Copula, which is easily supplied from the blood, and less of the Spirits, which are brought by the passage of the nerves, is bestowed.

And here it may be rightly inquired into, whether the Pulse of the Heart so necessarily depends on the influence of the animal Spirits through the Nerves, that it being hindred, the action of the Heart should wholly cease? For the decision of this, we once made a tryal of the following Experiment upon a living Dog. The skin about the Throat being cut long-ways, and the Trunk of both the wandring pair being separated apart, we made a very strict Ligature; which being done, the Dog was presently silent, and seemed stunned, and suffered about the Hypochondria convulsive motions, with a great trembling of the Heart. But this affection quickly ceasing, afterwards he lay without any strength or lively aspect, as if dying, slow and impotent to any motion, and vomiting up any food that was given him: nevertheless his life as yet continued, neither was it presently extinguished after those nerves were wholly cut ascunder; but this Animal lived for many days, and so long, till through long fasting, his strength and spirits being worn out, he died. The carcass being opened, the blood within the Ventri∣cles of the Heart, and the Vessels on every side reaching from thence, to wit, both the Veins and Ar∣teries,

being greatly coagulated, was gathered into clotters; to wit, for this cause, because the bloo•…•… though for the sustaining of life, it was in some measure circulated, yet for the most part it stagnated both in the Heart, and in the Vessels. The cause of which stagnation I can assign to no other thing, than that the Praecordia, the influence of the animal Spirits being hindred, wanted its u•…•…ual motions.

If it should be further demanded, from whence the animal Spirits (the passage, of both the wandring pair being shut up) should be supplied to the Heart continuing still its motion; I say, that this may be done by the returning Nerves, as from the knots of which many Cardiack shoots and fibres proceed; and besides, the end of either nerve meeting with the nerve sent from the upper infolding, is united. But we shewed already, that the animal Spirits may be carried either this way or that way within the passages of the nerves; wherefore when the necessity of life urges, the provision of the Spirits, though lesser, being sent from the aforesaid infolding, is received by the tail of the returning nerve, and from thence by a retrograde passage it was derived into the Cardiack branches, and at length into the Heart it self. Fur∣ther, there lyes open also another passage, and that perhaps more obvious, through the passage of the 〈◊〉〈◊〉 nerve: by this way in a man, as well as by the passage of the wandring pair, the Spirits are conveyed from the Brain to the Praecordia; yea also in Brutes a branch is carried into the Trunk of the wandring pair from the intercostal infolding; so that by this by-path some little rills of the animal Spi∣rits (if by chance their influence should be hindred through their wonted chanels) might be carried to the Heart. However that Experiment seems to conclude, that the motion of the Heart depends no less upon the inflowing of the blood, than upon that of the animal Spirit: the total privation of either takes away life; and Eclipse of the Spirits wholly takes away from the Heart its motive power; and by the defect of the blood (forasmuch as the sulphureous Copula is denied to the Spirit implanted in the Heart) the vi∣gour and elastick force of the Heart is supprest, so that the Pulse being by degrees weakened, life is by lit∣tle and little extinguished. Without doubt, in the finding out the tenour of the Pulse, we ought always to mind what the alteration of the animal Spirits, and what the fault of the blood may bring to it.

There is yet another consideration concerning the Nerves reaching from the Trunk of the wandring pair to the Heart, to wit, that by their passage, not only the solemn influence and state of the Spirits, for the equally performing of the vital Function, is conveyed; but also the instinct of every irregular motion, stirred up in the Praecordia by the force of the Passions, is in some measure trans∣ferred this way. I say, as to these, we ought to discourse and to shew by what means, as often as the impres∣•…•…ion of any Affection exercises the Imagination, or rather the Appetite, presently the Praecordia are disturb∣ed by the passage of the Nerves, and by reason of their various Affections the motion of the blood is di∣versly altered, But because in a man the irregular and extraordinary motions of the Praecordia depend on the intercostal Nerve as much as and perhaps more than on the wandring pair; therefore we think good to defer this Speculation till the Theory of that Nerve is proposed. In the mean time, we will proceed to the other branches of the wandring pair; and what next follows, we will inquire into the offices and uses of the returning Nerves.

The returning Nerve in the left side, going away from the wandring pair below the aforesaid infolding, and sent towards the Aorta, is reflected or turned back about its descending Trunk, from whence being carried upwards, it imparts shoots to the Muscles of the Trachea and the Larynx sent forth by a long tract from either side of the Nerve; then its top or height is united with a shoot meeting it out of the Ganglioform infolding, Fig. 9. n. **** h But the returning Nerve on the right side is reflected much higher about the axillary Artery, to wit, proceeding from the lower infolding of the wandring pair, and after the same manner is bestowed on the other side of the Trachea, Fig. 9. L. But either returning back about the knots of reflection, sends forth towards the Heart very ma∣ny shoots and fibres, which are inserted into its little ears, the appending Vessels or its Infold∣ings.

What the chief use of this Nerve is, we have already shewn; to wit, being rolled about on both sides the Artery, as it were a Windlace, it causes the little rings of the Trachea or Weasand to be drawn hither and thither, like the folds of a pair of Bellows, both for breathing and making a sound. But indeed either Nerve, forasmuch as it being reflected about the Artery, is carried upward into the part to be moved, doth move downwards the little rings of the Trachea or Wind-pipe by certain shoots of it; also foras∣much as either is terminated in the Nerve, sent from the Ganglioform infolding, it carries upwards the folds of the Trachea by other shoots of it. Hence a reason may be given, why the returning Nerves being out off, every Animal is presently dumb; to wit, because, unless the Trachea be moved, the breath being blown out, passing without any refraction through its cavity, as it were through a Pipe alike hollow in its whole passage, gives no sound.

Concerning these Nerves we ought to inquire, what is the reason of the difference, that the knots of re∣flection are not alike on both sides; also for what end the Cardiack branches proceed from both knots. As to the first, that the left returning Nerve, not as its pair, binds about the axillary Artery, some reason seems to be, because the left axillary Artery, arising below, is carried as the right, by a bending, and not a straight passage, into the Arm; wherefore the little cord of the Nerve, compassing about its Trunk, hath no fixed, but a very moveable knot of reflection, for that it might easily slide from its place. But it may rather be said, that it is for other uses, and those more necessary, that these Nerves com∣pass

about those Vessels after that manner. For when they, as it were Reins or Bridles cast on the blood∣carrying Vessels, by pulling them hither and thither, variously determine the course of the blood, it seems to be required, that one returning Nerve should bind together or constringe the axillary Artery, and the other the descending Trunk of the Aorta: for as often as there is need for the blood to flow for∣wards towards the Head more plentifully, the returning Nerves perform it easily, by pulling upwards the aforesaid Arteries: but the blood, after a sort, ought to be continually urged into the higher parts, lest other∣wise by its weight it should turn too much downwards; wherefore in all Expiration or breathing forth, when the Trachea drawing nearer together its folds, is contracted upwards, the blood about to descend the Aorta, is snatched upwards by one tract of the nervous little cord, and in like manner, the axillary Artery in the right side being shaken with it, the blood flowing in the whole ascending Trunk of the Aorta, is driven upwards a little swifter.

But besides this continual and equal snatching up of the blood towards the upper parts, it is some∣times occasionally urged towards the Head by a more intense and quick motion of the Trachea, and also by a more full and swift course. For as often as any Animal grows angry, the voice presently shews signs of such an Affection, and oftentimes by chiding, they make it sharp; as men, when they are angry, chide or brawl, and Dogs bark: Now from such an intension of the voice and chiding, as the upper rings of the Trachea, a reciprocation being there made, are often struck together; so the blood also (the Aorta being strongly drawn) is urged upwards by a copious afflux, so that it presently dyes the countenance and eyes of angry people with a redness, and induces to the Brain it self a greater heat and provocatives to anger, and a greater glowing or infiring to the Spirits by stirring them up. For the same reason, in Joy and Gladness, forasmuch as the Trachea is exercised by singing or laughing, the blood also is poured out more plentifully towards the exterior, and especially the upper parts.

And from hence the cause is plain, wherefore either returning Nerve sends forth Cardiack branches from the knot of reflection or turning back; to wit, that in those kind of aflections, the notice of which the Trachea in sounds or voices gives by the help of the Nerves, the Heart it self by its means also might be affected, For so, as often as we wrangle or brawl, the Heart being irritated, presently inkindles the blood more, and drives it forward more plentifully, as food for those Affections, towards the Brain. Also in laughter, great rejoycing, or singing, by the passage of those Nerves, the Heart being brought into a con∣sent or Sympathy, or joynt action, presently explodes or drives out the blood by a swifter pulse, and casts it hastily out, which otherwise would be heavy and troublesom by a slower motion or stagnation; where∣fore those sorts of actions, to wit, laughing and singing, are said to alleviate the Heart, because they make the blood more freely and readily to be poured out of the bosoms of the Heart, and also by the supplying help of the Lungs, to be emptied into the same.

Below the production of the left returning Nerve another noted Nerve is carried towards the hinder∣most region of the Heart, which being carried with a certain compass about its Basis, sends forth frequent shoots, which cover the left side of the hinder Hemisphere, Fig. 9. o. Then this branch meeting with ano∣ther pair sent from the opposite side towards the Heart, and distributing shoots into the right side of the hinder Hemisphere, is united with it, Fig. 9. q.

This Cardiack branch, destinated to the hinder region of the Heart, is produced apart below the rest, that it might be carried by it self to its Providence without the meeting with or implication of others; the pairs are ingraffed on either side, that they might accompany one another, and be together drawn in the same action of the Heart. It appears not plain, whether these nerves conspire with the other Cardiack nerves, arising above, reaching forth to the anterior Hemisphere of the Heart; or whether this pair effect not the Systole of the Heart, and the upper its Diastole. However it is, certain shoots of the kindred or stock of either, being ingraffed with others of another stock, communicate one with the other.

The Trunk of the wandring pair sends forth on both sides very many noted branches from the region of the Heart, which are spread on either side into all the Lobes of the Lungs, the Bronchia of the Trachia, and the Coat of the Oesophagus hard by descending, Fig. 9. s. s. s. Those which go into the Lungs pass every where through their whole substance, following the ramifications of the Veins and Arteries, and the Pipes of the Bronchia, which chanels of blood and air they variously climb over, and bind a∣bout through their whole tract.

When that so many noted branchings of the Nerves are bestoweed on the Lungs, it is a wonder, that by some they should be thought to be insensible and immoveable of themselves. Yea it is doubted by ma∣ny, whether these Bowels do cause the motions of the Systole and Diastole of themselves by their own en∣deavour. For that it is a received Opinion, That this reciprocation of the Lungs doth proceed wholly from the motion of the Thorax, and doth obey or observe its dilatation or constriction with a certain ne∣cessary dependency; viz. that the Breast being dilated or spread open after the manner of a pair of Bellows doth compel the ambient Air into the Trachea, which rushing into the Lungs, blows up and distends them; then the same Breast subsiding or sinking of it self, that the Lungs being pressed together with the weight of it, do breath forth the Air before intruded. In truth, however that I might judge, that the Diaphragma and the Muscles of the Breast do conduce much to Respiration; yet that these parts should perform this office alone, and that the Lungs are merely passive, I can∣not grant. For Respiration is chiefly instituted for the sake of the blood and the Heart, and its act is wont to be determined according to the various disposition of these, and to be altered

every minute of an hour almost according to the manifold necessity of the Pulse. But indeed the Lungs themselves are they (and not the Diaphragma or the Muscles of the Thorax) which the blood, boiling out of the Heart, passes through, and continually affects according to its temper, and the tenour of the Pulse: wherefore from hence it may be concluded, That the Lungs themselves do conceive the first instincts of their motions, and by the help of the aforesaid Nerves, do in some measure exercise them∣selves, and endeavour the Systole and Diastole, and design them according to the sense of its proper necessity; but when in these, Fibres requisite for local motion are wanting, therefore the Diaphrag∣ma and the Muscles of the Thorax help continually the endeavours of the Lungs, and by the cooperation of these, compleat breathing is effected. And so when Nerves of a twosold kind, to wit, some from the Spine being inserted into the Muscles of the Diaphragma and the Thorax, and others from the wan∣dring pair distributed into the Lungs, actuate the Organs of Respiration; for that reason it comes to pass, that the act it self of Respiration, of it self unforced and involuntary, may be at our pleasure somewhat restrained, interrupted, and diversly altered. The Sympraxis or joynt action of the Nerves of either kind, in the work of Respiration shall be shewed hereafter, when we shall speak particularly of the Nerve of the Diaphragma,

It yet appears more plain, that the Lungs are oftentimes the chief in the act of Respiration, because they being irritated from strange and improportionate objects, presently conceive irregular and violent motions; as when a vehement Cough is stirred up for the exclusion of any troublesom thing; to which motion the Diaphragma and the Muscles of the Thorax presently obey. In like manner, in difficult and sighing breathing, or any other ways unequal, its first instinct for the most part is begun by the Lungs; yet sometimes when the exterior Organs of Respiration are excited into irregular motions, the Lungs also are compelled to follow their irregularities; so when the Diaphragma after a manner begins laughter, the Lungs perform the same with a following cackling sound: so all the Organs of Respiration intimately conspire and agree among themselves, that although one of them do a thing inordinately, rather than there shall be a Schism, the rest do imitate or follow its irregularity.

But that the Nerves, following the Arteries and Veins through the whole frame of the Lungs, do va∣riously bind about and cloath their Trunks with a thick series of shoots, the reason seems to be, both that the Coats of the Vessels being gifted with a constant influx of animal Spirits, might inmitate the motion of the Heart; and by that means, by a continual pulsation of the Arteries and the constriction of the Veins, they might easily carry the blood in this its more short lustration through the Lungs; and the rather, that the pneumonick Vessels, being bound about with such Reins of Nerves, might moderate the course of the blood according to the forces and instincts of the Passions. For whenas the exterior circulation of the blood depends upon this interior; as the blood is commanded to pass sooner or slower through the Lungs, or to stay there and be hindred, the excursion and return of it also from or towards the Heart is wholly performed. In Joy or Anger, because the Lungs rapidly transfer the blood out of one bosom of the Heart to the other; therefore its swifter and more plentiful flowing out into the outward parts, follows. In like manner, in Fear and Sadness, for that the Lungs (its Vessels being strained together) deliver the blood to the Heart by the Veins, and do not then presently carry it back by the Arteries, the outmost region of the Body is destitute of its due influx. Notwithstanding these kind of pathetick snatches of the blood are in some measure performed, because its Vessels are bound about in other places in like manner with the Nerves. If at any time Spasmodick Affections should afflict the pneumonick Nerves from a morbific cause, so that being twitcht with inordinate motions, they should pull or draw together here and there the Arteries and Veins which they embrace; for that cause, the blood either too much flowing out of the Lungs, makes them to flag, and to fall together into themselves, so that draw∣ing to them copiously the Air, they do not easily render it back again; or, which frequently happens, the blood being detained within the Lungs, and there stagnating, stuffs them up, and holds them a long while stiff, that they cannot inspire or draw in the Air. The Symptoms of either kind ordinarily happen in the Hysterick distempers, and in some Hypochondriacal. Yea sometimes the Bronchia themselves are pulled together by the like Convulsion of the Nerves, and are hindred in their motion, so that they can∣not take in and send forth the Air after its due manner, as may be seen in Asthmatical Fits. The dis∣tempers of which sort are oftentimes produced by the fault of the Nerves, without any implanted Dyscrasie or evil disposition of the Lungs. I have sometimes observed some Cases of sick people, in which, when at one time the morbifick matter besieging the Brain, had induced Lethargick or Vertiginous Symptoms, a little after the same matter occupying or possessing the origines or middle processes of the nerves belonging to the Lungs, has suddenly excited a most horrid Asthma without any previous Cough or Cataih.

But that out of the same tract of the wandring pair many shoots are distributed into the Lungs and al∣so many others into the Coats of the Oesophagus; from hence a reason may be given, why a troublesom Cough oftentimes causes Vomiting and a subversion of the Ventricle; why also on the other side a per∣trubation of the Ventricle so frequently induces a troublesom endeavour of Coughing. I have known in Hypochondriacks, that aliments of ill digestion, taken into the Stomach, have presently excited a vain and very pertinacious Cough; in the mean time, that the Lungs were free from any consumptive disposition. The cause of either distemper seems to be, that when the nerves, disseminated in either part are taken with a Convulsion, oftentimes those which are of the other part, are drawn into a consent of the same distem∣per.

Perhaps from hence it happens, that sometimes an Asthma is induced by reason of the evil of the Ventricle, and that that distemper (as Riverius observes) is often wont to be cured by an emetick Medicine.

After so many branches and shoots have been sent from both sides the wandring pair, at length its Trunk is divided below the Lungs into two branches, viz. the exterior and interior; either of which in∣clining towards the pair of branches on the other side, are united to them, and after a mutual commu∣nication they constitute the two Stomachical branches, viz. the superior and the inferior, Fig. 9 A. u. w. x.

It is worth observing, with what wonderful artifice either Trunk of the wandring pair do commu∣nicate one with the other with two branches, as it were two hands meeting one the other, that the influ∣ence of either nerve might equally reach to every region and part of the Stomach. For when as either Stomachical branch, to wit, both the upper and the lower, is carried together from the two branches com∣ing out from either side of the wandring pair; it is provided, that the Tributes of the Spirits destinated to the Ventricle, should be at once certain and very plentiful. For what appertains to the performing the action of this Bowel or Chylification, the Spirits flowing in from either side, are abundantly distributed into the Orisice, and from thence into all its parts and private places; and by that means it comes to pass, that the Stomach dissolves bodies beyond the force of any Chymical Menftruum. Then besides, as to the feeling or sense of the Ventricle, or the affection of it from things ingested; it is carried also towards the Head by a double way (whereby the passage may be the more certain) to wit, by either Trunk of the wandring pair; that for that reason being endued with a most exquisite sense, it might not be deceived con∣cerning its objects; and if that any thing inimical or contrary to it, should lye hid among what is eaten, it might discern it and thrust it out of its own accord, or at least by the knowledge only of the Cerebel.

That from the same double Trunk of the wandring pair, from whence the Cardiack Nerves arise a little above, the Stomachical branches also proceed, the cause is plain, wherefore the Heart it hath such a Sympathy with the Stomach, so that its Deliquium or Swooning follows upon any great pulling or hawling of this.

Either Nerve of the wandring pair is terminated in the Ventricle it self: for after the eighth Conjuga∣tion hath made as it were an high road for the passage of the animal Spirits to the Praecordia and to this noble Bowel, it puts a bound to it self; nor indeed does it seem meet to have its branches stretched out a∣ny further to the Viscera of the lower Belly: because it seems an unworthy thing, that the same path which leads to the chief office of nutrition and to the Palaces of life it self, should lye open to the more vile In∣testines also, and the sink of the whole Body. And truly, although the ample path and broad way of the wandring pair is not produced beyond the Ventricle; yet because a frequent commerce happens between this and the Praecordia and the other inferior parts; therefore between the Stomach and the other Bowels, though of a more base use, certain Fibres, as it were smaller paths, are reached forth, in which, at least little bands of Spirits, like Discoverers or Messengers, run to and fro.

CHAP. XXV. A Description of the Intercostal Nerve.

AFter the unfolding of the Nerve reaching forth to the Praecordia and the Ventricle, we are led by the series or order of the inward parts to the describing a Nerve a kin to this, and which reaches forth its branches to the furthermost Province, to wit, to all the Viseera or Inwards of the lower Belly contained below the Ventricle. This is commonly called the Intercostal, because that going near the roots of the Ribs, it receives in every one of their Interstices a branch from the spinal Marrow. Its beginning is not yet sufficiently detected; for by most Anatomists it is wrongfully taken for a branch of the wandring pair, though indeed the wandring and the intercostal pair do communicate among them∣selves by branches sent forth one to the other; yet as to both their beginnings, Trunks and wandrings up and down, they are plainly distinguished. If that this latter Conjugation, being denied the title of a pe∣culiar nerve, ought to confess it self of another stock, certainly it owes nothing to the wandring pair, but should borrow its original from the Nerves of the fifth and sixth pairs; for two or three shoots being sent back from those nerves going out towards the Eyes and Face, go into the same stock or Trunk, which is the Trunk of the intercostal nerve, as we have intimated before.

The intercostal Nerve being constituted after that manner, and going out of the Skull at a proper hole, presently contains the Ganglioform infolding, Near to another the like infolding of the wandring pair; into which two nervous Processes are carried from the last pair within the Skull, or the first vertebral. From that infolding one shoot is sent forth into the Sphincter of the Throat, and another noted one into the Ganglioform infolding of the wandring pair. Then this nerve descending towards the

Vertebre, hath in the middle of the Neck another far greater infolding, into which an ample nerve, from the neighbouring Vertebral pair, is inserted; but from the same many nerves, which respect the Praecordia, are distributed on every side: For two or three shoots are sent forth into the nerve of the Diaphragma, and one shoot into the returning nerve; besides numerous fibres and shoots are carried both into the re∣turning nerve, and towards the Trachea, which are inserted into its Coats, and into those of the Oesophagus, and into the blood-carrying Vessels. Further, one branch descends into the Trunk of the wandring pair, and two noted nerves into the Cardiack infolding; then a little lower another nerve by it self, proceeding out of the intercostal Trunk, is inserted also into the Cardiack infolding: which noted branches sent down on both sides from the intercostal nerve, for that they joyn together with others de∣rived from either Trunk of the wandring pair, make the Cardiack infolding it self. But these Cardiack branches from the intercostal nerve, as also the Cervical infolding, or that in the hinder part of the Neck, whence they proceed, are peculiar to men, and are wholly wanting in brute beasts.

The intercostal Trunk descends from the cervical infolding towards the chanel-bone, where being a∣bout to enter the cavity of the Breast, it falls upon the axillary Artery, as it were in right Angles, and strains or binds it; from whence it is drowned or hidden in the Thorax near the roots of the first and se∣cond Ribs; and there receiving three or four branches from the Vertebral nerves next to those uppermost, constitutes another infolding, which is commonly called the Intercostal infolding. The uppermost of these Vertebral nerves coming to this infolding in its journey binds the Vertebral Artery, and almost compas∣ses it about. In Brutes by this nerve which comes upon the Vertebral Artery, the intercostal infolding communicates with the root of the nerve of the Diaphragma, and not by any other means, unless by small fibres sent forth from the lower part of the infolding into the Vertebral nerves. Further, in Brutes a noted branch is carried from this infolding into the Trunk of the wandring pair. But in Man the intercostal Trunk passes through the cavity of the Thorax without any communication had with the other parts; un∣less that from hence in its whole descent, running near the roots of the Ribs, it admits in every one of their interspaces and from thence even to the Os sacrum from between the knots of the Vertebrae, a Verte∣bral branch.

The intercostal pair sends forth a noted branch on either side, where having gone through the cavity of the Thorax or Breast, it comes over against the bottom of the Ventricle, which tending towards the Me∣sentery, constitutes the chief infoldings of it. But there are seven Mesenterick infoldings, viz. five great superior, and two less inferior: out of all which, numerous shoots and fibres are sent forth together into the parts which they respect, and into the neighbouring infoldings. The Mesenterick nerves, which are carried into these infoldings, and the infoldings themselves, and also the fibres and shoots, which flow out from them on every side, like rays of light, are disposed according to the following manner both in Man and in the more perfect Brutes.

The Mesenterick branch therefore in the left side going from the intercostal Nerve, and bending down∣wards, is parted into two noted shoots: the greater of these bending back upwards towards the Stomach, diffuseth it self presently into an infolding, as a narrow rivulet into a spacious Pool. From this infolding numerous fibres and shoots go forth as it were in four bands. The first of these, and which is the greatest bundle of its fibres, being carried into the Ventricle, is bestowed partly in the bottom of it, and partly these fibres are met, and ingraffed with others sent from the Stomachical branch. The other maniple or band of nervous Fibres goes forth from this infolding to the Spleen, where the nerves accompanying the sanguiferous Vessels, and variously binding them about, are dispersed into the more inward frame or sub∣stance of the Spleen; yet out of which going towards the Spleen, some shoots following the short Vessels are carried into the Stomach. The third Company of nervous Fibres is inserted between this infolding, and the Hepatick or that belonging to the Liver, placed in the right side over against it. Lastly, the fourth Conjugation of Fibres knits together this and the greatest infolding of the Mesentery lying under it.

The lower shoot of the Mesenterick branch, which is on the left side, increases into an infolding, to which the next Vertebral branch, destinated to the intercostal Nerve, is carried. From this infolding the chief bundle of the nervous Fibres is carried into the left Kidney, and before the Fibres enter the Reins, they bind and variously compass about the emulgent Vessels. Further, between this infolding and the great∣est of the Mesentery many Fibres are stretched out; from hence also many shoots are distributed into the atrabilary Chest, or the Receptacle of the Spleens excrements.

In the right side the Mesenterick branch being sent from the intercostal Trunk, and being in like manner twofold, contains in its upper shoot the Hepatick infolding; out of which the greatest bundle of nervous Fibres is carried towards the Liver; numerous shoots of which accompanying the blood-carrying Vessels, greatly beset, and as it were cloath with a little net the Trunk of the Hepatick Artery: which Fi∣bres and shoots, being carried higher, are distributed into the Liver, Gall chest or bag, the passage of the Gall, the Pylorus, and the Pancreas. Further, many Fibres, which are of this Conjugation, meet with Fibres sent from either Stomachical nerve, and are ingraffed into them. Another hand of nervous Fibres is stretched out between this infolding and the opposite infolding to the Spleen, and another between this and the greatest infolding of the Mesentery; yea, there is some communication had between this and that belonging to the Kidney lying under the same side by a large shoot sent down.

The lower shoot of the right Mesenterick branch, like as it is in the opposite side, contains a sufficient∣ly noted infolding nigh the atrabilary Chest; to which presently the intercostal Nerve imparts its Vertebral branch received below. From this infolding the chief bundle of nervous Fibres destinated to the Reins, embraces the blood-carrying Vessels in like manner as in the opposite side; also many fibres and shoots are stretched out from this infolding to those near, viz. the Hepatick and the greatest of the Mesentery; yea, certain Fibres are dispersed from the same into the atrabilary Chest.

After this manner either Mesenterick branch being carried from the intercostal pair, and being present∣ly twofold, immediately constitutes two infoldings in either side. In the midst of these the infolding of all stands like the Sun in the midst of the Planets; from which numerous shoots and fibres are dispersed into all the parts of the Mesentery; which indeed following the blood-carrying Vessels in their whole process, climb over and bind about the same. Moreover, between this infolding and every one of the four afore∣said is produced a peculiar little bundle of Fibres. Besides, in the female Sex, from hence some shoots are carried into the Glandula's of the Womb, commonly called the Stones. But from the Mesenterick branches, which constitute the former infoldings, no noted branches, but only little shoots, are sent into this infold∣ing. Yea the chief Nerve which is inserted to this, and seems to be the primary for the coveying of plenty of Spirits into it, and a broad way, is carried from a certain small infolding far lower nigh the straight Intestine; which infolding, together with the other neighbouring one, that we call the lesser in∣foldings of the Mesentery, shall be described presently. In the mean time, that we may proceed to them in order, we will follow the passage of the intercostal Nerve.

Below the Mesenterick branches, from which the aforesaid superior infoldings are constituted, the inter∣costal Trunk descends between the Muscles of the Loyns, and bestows every Vertebral branch, admitted in its descent, upon some internal parts.

For the Vertebral branch brought to the intercostal Trunk nigh both Kidneys, is carried into the Wo∣mens Testicles, then some following into the Ureters. From the Region of the twenty seventh Vertabra one Vertebral branch and two others, going from the intercostal Trunk, tends towards the strait Intestine, and there they meet with three pair sent from the other side; all which being united, constitute the in∣folding, which is the lowest of the Abdomen. From this infolding a noted Nerve, being carried upwards, is brought into the greatest infolding of the Mesentery, which in its journey receives one and then ano∣ther shoot sent down on both sides from the intercostal Nerve; and there, near its bounds, distributes some shoots into the Glandula's of the Womb.

But from the lowest aforesaidin folding, a Nerve going towards the upper Infoldings, about the space of an inch, constitutes another lesser infolding in the neighbourhood; out of which one Nerve tends upwards, and another opposite straight downwards. The former of them is carried into the greatest infolding of the Mesentery, and in its whole passage stretches under the straight Intestine, and part of the Colon, and inserts into the•…•… many small shoots. But the other Nerve descending from this infolding towards the Anus under the inferior part of the straight Intestine, imparts to it also frequent shoots; so that this infolding, the least of all those which are within the Abdomen, seems to be constituted for the sake of this Nerve only, to wit, which lying under the straight Intestine and part of the Colon, is inserted into the greatest infolding of theMesentery.

From the lowest neighbouring Infolding, to which this least owes its original, two Nerves going out, and being sent down into the Pelvis, cause there two infoldings, viz. one in either side, in which the Nerves coming from the Os sacrum, and ingraffed with the former, meet; from which also the Nerves distributed into the abjacent parts, serve unto the several Excretions, viz. of the Urine, Dung, and Seed made in that place: for two Nerves enter into the end of the straight Intestine, and as many into the Womb or Prostates; but one and that noted one, is carried into the Bladder.

But that we may return to the Intercostal pair, after either Trunk of it had sent forth three branches, out of which the aforesaid lower infoldings of the Abdomen are mediately or immediately made, it de∣scends straight towards the Os sacrum, and in its journey sends forth yet one or two branches into the Ureters: but as soon as it is come to the beginning of the Os sacrum, both nerves mutually inclining them∣selves to one another, are demerged within the bending of the same bone, and there nigh its declining, and then in its descent, they seem to be knit together upon it by two or three processes; and so at length either nerve ends in very small fibres, which are distributed into the Sphincter of the Anus. But some∣times either nerve joyn together into a round infolding nigh one transverse process, out of which single infolding the like very small Fibres are produced. Further, many others from the last Vertebral Nerve meet with, and are ingraffed with these Fibres from the intercostal pair inserted into the Anus.

CHAP. XXVI. The Explication of the Intercostal Pair of Nerves which are described in the former Chapter as to their Offices and Uses: and first the upper Branch∣ing of them is considered.

THE beginning of the Intercostal Nerve are two or three shoots reflected or turned back from the Nerves of the fifth and sixth pair, and united into the same Trunk, Fig. 9. D. a. a. b. Here we may wonder at the birth of this Nerve, as it were borrowed; for it grows as a shrub upon another tree or shrub; and therefore dispenses the common virtues and influences of either with a double branching viz, both its own and that of its parent: by which ramification or branching it comes to pass, that there are very quick commerces and consent between the conceptions of the Brain and the affections of the Pr•…•…cordia, also between the Actions and Passions almost of all the parts of the whole Body, which belong to the involuntary Function. For in that the Trunk of the intercostal Nerve proceeds from the Nerves of the fifth and sixth pair nigh their beginnings, that is a sign that both the influence of the animal Spirits, and the instincts for the performing of motions, are derived chiefly into it from the Cerebel; to wit, from whose annular process the aforesaid pairs of Nerves arise. But forasmuch as the same intercostal Nerve is rooted in their Trunks, and not immediately in the Cerebel; this is the reason why the Eyes, as also the parts of the Mouth and Face, to which the fifth and sixth pairs have regard, do answer so readily and unknown to the Cerebel, as it were by the same act, to the motions of the Praecor∣dia and Viscera, which the intercostal Nerve effects; and on the contrary, the motions of these presently follow the action of those. As for example, in Sneezing as soon as the nervous Fibres besmearing the Nostrils, are wrinkled together by the pulling, presently by the passage of the intercostal nerve the Diaphragma, by reason of a more deep inspiration or drawing in the breath, is for some time depressed; then the Cramp of the Nostrils remitting, the Midriff also being violently drawn back, causes a more strong breath∣ing forth with a vehement blowing of the Air. In like manner on the contrary, when by a tickling made upon the Ribs, the Diaphragma being affected with a Spasm, moves to a cackling noise, the Face and Mouth are pathetically figured with it into laughter.

The intercostal Nerve being slid out of the Skull, presently constitutes the Ganglioform infolding Fig. 9. G. it being after the same manner in the Trunk of the wandring pair. What the use of these infold∣ings is in general, we have already shewn; and clearly for the same reason in this place in the intercostal Trunk, where it receives into it self some nerves from elsewhere, and sendsforth others from it self into the neighbouring parts, this infolding, as it were a knot in the stem of a flourishing Tree, is made, that it may be as it were a diverting place for the manifold tendency of the Spirits. As to the adventitious Nerves it is observed, That by them plenty of subsidiary Spirits are transmitted hither, only from the spinal Mar∣row, but by a manifold and frequent passage; wherefore in this infolding, and again in the following, then a little lower, nigh the several junctures of the Vertebra, the Vertebral branch comes to either Trunk of the intercostal pair: this seems to be so constituted for many uses. First, That the intercostal Nerve, by the reit•…•…rated fastening to the solid parts, as it were by a frequent stay, might become the more firm for the making of a long journey, when otherwise its little rope, by too much stretching out, might be easily broken. Secondly, By this means it comes to pass, that the nerves which are the Executors of the spontaneous, and those of the involuntary Function, might have both a more certain commerce together, and might be sometimes excited into mutual succors. Hence Respiration and some other Acts, especially what concerns the Act of Venus, participate of either Regiment, so that sometimes they follow the will, and sometimes draw it even by force or unwilling. Further, when at any time the stock of animal Spirits is deficient in either Province, supplies of them are sought from the other: to wit, (as we hinted above) if the influence towards the Pr•…•…cordia be shut up through the ordinary passages, viz, the internal nerves, their passages requisite for the sustaining of life, might be supplied by the Vertebral branches: yea it is probable in the partial Apoplexi•…•…, and in the 〈◊〉〈◊〉 or Night-mare, when the Cerebel being affected, the Spirits destinated for the Heart, suffer an Eclipse in the Fountain it self, that through these Emissaries, to wit, the Vertebral branches inserted into the intercostal pair, some extemporary Subsides are carried for the actuating the Heart. Thirdly, The Vertebral branches by so frequent an insertion, are added to the intercostal nerve, perchance in some respect for this end also, that the superfluous or excrementiti∣ous humidities, heaped together about the spinal Marrow, might be sent away by these Processes: for indeed we have already shewn, that a certain humor doth abound within the Head, the medullar Appen∣dix, and nervous System; which oftentimes (when it becomes watry, or abounds above measure) begets a serous heap in those parts: wherefore when the branches of the intercostal nerve are terminated into the Mesentery, Kidneys, Intestines, and some Genital parts, it is probable they do transfer into these sinks superfluous humidites, not only their own, but also of another sort, to wit, those received from the spinal Nerves.

As to the Nerves, which as Emissaries, are carried from the aforesaid Ganglioform infolding into o∣ther parts, we observe; first, that a noted shoot is carried from hence into the Sphincter of the Throat, Fig. 9. γ. This nerve in the Sphincter of the Throat corresponds with others akin, arising higher from the fifth pair, and distributed into the parts of the Palate and Mouth, and is helpful to them in the business of chewing: for when the maxillar branches of the fifth pair should perform their work for the chewing of the food taken in, the task of this nerve mediately arising also from the fifth pair, follows to wit, whereby the Throat being opened, the chewed meats may be thrust forward into its pas∣sage.

Another shoot is stretched out from this infolding into a like infolding of the wandring pair placed near, Fig. 9. α. The reason of this insertion is delivered above, where we treat of the wandring Pair. But it may be obs•…•…rved further concerning this; when so nigh a communication happens between these in∣foldings, and when shoots are sent from one of them into the Muscles of the Larynx, and from another into the Muscles of the Throat, from hence we may give a reason, why in Hysterick distempers and in some Hypochondriacal, here is so frequent and familiar a Symptom of the sense of choaking in the Throat. For a Cramp or Convulsion being begun in any Nerve, it is wont to creep forward further by the pas∣sage of the same, and so to invade sometimes these parts, sometimes those successively. If therefore at any time a Spasm arises any where in any nerve of the wandring or intercostal pair, and from thence sending upwards or downwards, shall come to either infolding, presently both being affected, and the Muscles of the whole neighbourhood being contracted, a bulk or Tumor like a Globe or round thing in the Throat is excited with a sense of choaking,

The intercostal Nerve descending a little lower, contains in the neck another greater infolding proper to man, to which a noted Vertebral nerve is inserted also, out of which many nerves destinated to the Prae∣cordia, are sent forth on either side, Fig. 9. T. As to the principle parts, to wit, the Brain and Heart, there is no such great difference between a Man and a Brute, as there is about the passage of one to the other, or the commerce that those parts have mutually among themselves. In either kind, for the exercise of the vital Function, the animal Spirits are derived from the Head, with a constant emanation into the Heart; to which sort of influence of theirs the passage of the wandring pair of nerves seems sufficient: wherefore in most Brutes the passage to the Heart and its Appendix lyes open only by this way, and scarce at all by any nerves of the intercostal pair. But in Man the intercostal nerve, besides its offices in the lower Belly, common to him with other Animals, serves in the place of a special Internunicus also before the Cloister of the Breast, which bears the mutual senses of the Brain and Heart this way and that way, or to and fro. For when, besides the nerves of the wandring pair, stretched out also into the hu∣mane Praecordia, (which certainly seems sufficient for the executing of the offices of the Function merely vital) so many noted branches are sent forth from the aforesaid intercostal infolding, what kind of office should be attributed to these, unless that they should contain the animal Spirits, by whose work and mi∣nistry, the mutual respects and affections of the Brain and Heart should be communicated to one another? Whilst I consider this difference of either kind, it comes into my mind, that Brutes are like Machines framed with a more simple furniture and with less workmanship, and therefore furnished with a motion of one kind only, or determined for the doing still the same thing. But in Man divers series of motions, and as it were complications of wheels within wheels, appear. For indeed, by the passage of the aforesaid infolding, the conceptions of the Brain presently affect the Heart and its Vessel, and cause the rest of the Appendix, together with the Diaphragma, to be moved. Hence the motion of the blood and its inkindling in the Heart, together with the Pulse and Respiration, are altered: and for that cause, from the Heart being altered, not only impressions are retorted upon the Brain by the passage of the same nerves, but also the blood it self, its course being changed, drives to the Brain with a different or unaccustomed fluctuation, and so by moving the animal Spirits with various impulses, causes first one sort of concepti∣ons, and then others to be produced: and so by reason of these reciprocal affections of the Heart and Brain, which are wont by a long series to be propagated vicissively, a multiplicity of thoughts and Phant∣asms arises. Hence both the ancient Divines and Philosophers placed wisdom in the Heart. Certainly the Works of Prudence and Vertue depend very much on the mutual commerce which happens to the Heart with the Brain: because, that cogitations about the acts of the Appetite or Judgment may be rightly de∣scribed, it is behoveful for the flood of the blood to be restrained in the Breast, and the inordinations of it and of the Heart it self to be governed by the Nerves, as it were by Reins, and to be composed into re∣quisite and apt motions. We might say more concerning this, but that this Speculation is from our pur∣pose, and belongs more properly to Pathology or the Doctrine of the Passions of the Soul, in the mean time, we may refer hither one or two Observations taken from Anatomy.

When of late we had dissected the Carcass of a man that was a Fool from his birth, we could find no defect or fault in the Brain, unless that its substance or bulk was very small. But the chief no•…•…e of difference which we observed between the parts of this man and of a man of judgment, was this, That the aforesaid infolding of the intercostal Nerve, which we call the Internuncius of the Brain and Heart, proper to man, was very small in this Fool, and beset with a weaker guard of Nerves,

Whilst we were writing these, we made an Anatomy of a Monkey, whose Brain differed little from that which is seen in a Dog or a Fox, unless that it was much more capacious in the proportion to the bulk of his Body, and the turnings and windings of it were larger. The orbicular Prominences called

N•…•…tes and Tes•…•…es, also the ringy Protub•…•…ance, sen•…•… down from the Cerebel, came nearer the figure and magnitude of those parts in a man. But what occurred chiefly worthy noting, was this, viz. That the intercostal Nerve, although even as it is wont to be in other Brutes, being included in the same sheath with the Trunk of the eighth pair, was carried through the Neck, yet departing from this Nerve near the Chanel-bone, before it was inserted into the infolding, placed nigh the roots of the upper Ribs, did send forth some shoots into the Heart 〈◊〉〈◊〉 its Appendix, and certain Fibres into the nerve of the Diaphragma: which perhaps partly is the reason, why this Animal is so crasty and mimical above other Beasts, and can so aptly shew and imitate, not only the gestures, but the passions and some manners of a man. But we will proceed to the explication of the intercostal Nerve from whence we have digressed.

We have already intimated for what use the Ve•…•…tebral branch is inserted into its cervical infolding. There is the same reason for this as for the other Vertebrals, which communicate with the intercostal Nerve almost in its whole passage. But for that the nerve of the Diap•…•…agma is radicated in the same Verte∣bral nerve, from whence a branch comes into this infolding, I say from that a reason may be taken, why the motion of the Di•…•…phragma intimately conspires with the Pr•…•…erdia, yea and with the conceptions of the Brain: which kind of Sympathy of the Diaphragma with the other parts, because it is requisite to be more strict and noted in man, it is observed, That not only the Vertebral branch cometh between the infolding and the root of the nerve of the Diaphragma, but two and sometimes three nerves are sent from this infolding into the trunk it self of the nerve of the Diaphragma, Fig. 9. ε. ε. Truly from hence not only the joynt action or Sympraxis of the Diaphragma with the Praecordia may be derived; but also the genuine cause is here manifest, why Risibility is a proper Affection of a man. For as often as the Imagina∣tion is affected by any pleasant or wonderful conception, presently the Heart desires to rejoyce, and as it were by shaking off its load to be eased: wherefore that the blood might be more swiftly emptied out of its right bosom into the Lungs, and consequently out of the left into the Aorta, the Diaphragma, instigated by the passage of the nerves going out of this infolding, is drawn upward by a more rapid Systole, and raises up the Lungs, as it were making iterated leaps, and causes them, by their more frequent striking together, to drive out both the Air and the blood. Then forasmuch as the same intercostal Nerve, which communicates lower with the nerve of the Diaphragma, is continued also higher with the maxillary Nerves, a cackling being made in the Breast, with it the gesture of the Mouth and Face pathe∣tically answers.

One or two noted shoots and many nervous Fibres are carried from this infolding into the returning Nerve, Fig. 9. ζ. Certainly the reason of this communication seems to be, that the Diaphragma and the Heart it self (into which nerves are sent from this infolding) might yet more conspire with the rough Artery (which the returning nerve affects) in its various actions, and especially in laughing, weep∣ing, and singing. Moreover, when the returning Nerves, by pulling upwards the Trunks of the Aorta, cause the blood, for the stiring up some Affections, to creep more swiftly towards the Head, they may in the performing that office be much helped by the associate labour of the Nerves sent from this infolding.

From this infolding in the Neck many small fibres and shoots are spread into the sanguiferous Vessels, as also into the Coats of the Trachea and the Oesophagus, Fig. 9. ibid. As to what belongs to the former that respect the Trach•…•…a and the blood carrying Vessels; their office is, that they may respectively draw together and spread abroad those channels of inspired and expired blood and Air, according to the way and manner where with the Pulse and Breathing ought to be performed; whereby the motions of either might be the better retarded or accelerated, according to the necessities or requirings of the Heart. Then numerous Fibres are stretched out from this infolding into the Coats of the Oesophagus placed near, that by this means the admirable consent between the Heart and the Stomach, by reason of the Nerves being reached forth from this infolding and from the wandring pair to both, may be produced.

Concerning the Cardiack branches sent from this infolding, we need not discourse any more: after having but now intimated, that these were as it were Intern•…•…neii peculiar to men, which carrying to and fro the reciprocal impressions of the Brain and Heart, cause Commerces in both Kingdoms. But forasmuch as Nerves of a double kind, viz. of the wandring and intercostal pair, respect the humane Praecordia, lest the gestur•…•…s of one should be different from those of the other, therefore the 〈◊〉〈◊〉 branches, which are of either family, partly communicate in the same infolding, and are partly 〈◊〉〈◊〉 mutually by shoots sent forth before they are distributed into the Heart it self.

Below the Cervical infolding, the intercostal Trunk being demersed within the Thorax, admits three Vertebral Nerves arising higher, and constitutes the other infolding, which is commonly called the Intercostal, but more properly the Thoracic•…•… infolding, Fig. 9. θ. In this place the intercostal Nerve being about to pass into its last and more large Province, viz. the Vise•…•…ra of the lower B•…•…lly, and therefore seeking aid for the journey, and as it were a Viati•…•…um for it self, it gets together in this infold∣ing an increase or aiding forces from the Vertebral nerves, and afterwards receives lower others fresh nigh the several knots of the 〈◊〉〈◊〉 because it will have need of a great stock of the Spirits, which it must 〈◊〉〈◊〉 on the Mesenterick infoldings, and on other parts of the Abdomen.

That this Nerve about to enter the Thoracical infolding, doth bind the Chanel-bone Artery, Fig. 9. 1. and that the superior branch of the Vertebral, being sent into the same infolding, doth bind about the Vertebral Artery, Fig. 9. π. the reason of both seems, that the blood, for the uses and necessities of the lower Visc•…•…ra (to which the intercostal Nerve from thence serves) may be driven forward with a more plen∣tiful afflux downwards: which thing those Nerves easily do by pulling together the blood-carrying Ves∣selstowards their infolding; so that they attempt this snatching of the blood in opposition to that which the returning Nerves perform. And indeed when the blood, tending upwards and downwards is wont sometimes to flow too much towards either bound, sometimes to be wanting; therefore the nerves, as it were an incitement or remora, are variously disposed both in the upper and lower region of the Circuit about the sanguiferous Vessels. After what manner this Thoracical infolding is in brute Beasts, shall be particularly shewn hereafter. The intercostal Nerve in a Man, both in this infolding and in the whole descent through the Thorax, receives many Vertebral nerves, as if sparing of its own stock, and greedy of anothers, but sends forth from it self not a shoot: whatever of Spirits is remaining either from the influ∣ence above, or comes to it by the by, is reserved wholly for a largess to be bestowed on the Viscera of the lower Belly, But after what manner, and by what passages of nerves that is dispensed into the several parts, we will unfold in the following Chapter.

CHAP. XXVII. The lower Branching of the Intercostal Nerve belonging to the Parts and Viscera of the lower Belly is unfolded.

AFter the intercostal Pair hath past through the hollowness of the Thorax without any expence of Spirits, unless in the Neck-infolding, at length it sends down from the region of the Ventricle on both sides, a noted Branch; either of which presently becoming divided into two, constitute two peculiar Infoldings on either side; but one infolding arises in the midst of them, as if com∣mon to either side. Of the infoldings which are on the left side, one respects the Kidney, and the other the Ventricle with the Spleen; but of those which are on the opposite side, one respects the right Kidney, and the other the Liver and its neighbouring part. In the midst of these, the infolding proper to the Me∣sentery and the biggest, is placed as the Sun among the other Planets. Further, from these are sent forth one to another and into the neighbouring parts numerous Fibres very thickly, as it were dartings of rays. Fig. II. plainly shews all these.

Concerning these, in the first place, it shall be inquired into in general, For what end so many nervous infoldings, with almost innumerable fibres and shoots, are distributed about the Mesentery and the Viscera of the Abdomen. For when in these parts the fibres and nervous shoots are carried on every side with so thick a series, that they are variously infolded with their manifold meeting, it may seem wonderful, if every one of these be destinated to some uses, and are not rather sprinkled here and there by chance, and as it were by the inconsiderate sporting of Nature. And indeed any one can scarce think, that so many Vessels should be prepared for the performing the offices of motion or sense in that place. For those Vis∣cera, unless highly pulled and affected with a Convulsion, are sensible of little or nothing that we know of; and their motions are almost no other thing than obscure Vermiculations or light Corrugations, so that for the effecting them there is required no greater preparation than for the slow progress of a Snail. Wherefore from hence it hath come into the mind of some, that a certain Juyce, and that perhaps nu∣tritious, was dispensed by this manifold passage of the nervous Pipes: which sort of office however if assigned to these Fibres dispersed about the Mesentery, why should not the same office either of receiving or of carrying of nourishment, be granted to those in like manner divarlcated about the Lungs and the Praecordia, and especially about the rough Artery? But truly it is highly improbable, that a nutritious Juyce should becontained in the Coats of the Trachea or of the Bronchia, which the nerves may suck out; nor does it more clearly appear, why more nerves should be destinated for the carrying of the alible Juyce to these parts of the Abdomen, or those of the Breast, than is needful for the musculous stock. But in the mean time, though we deny, that the whole nutritious matter is carried this way and that way by those or the other nerves; yet we think, that within those nervous passages an humor doth perpetually abound, which may be for a Vehicle of the animal Spirits, and a Ferment for the nutritious matter: with which going with the nervous humor towards the Intestines and to the other sinks of the Body, it is likely, that the superfluous and excrementitious serosities do often slide down together, and so are carried out.

But it may be well thought, as to the Mesenterick Nerves, and Infoldings in which they are terminat∣ed, and the Fibres most thickly going out of these, that these different manner of Vessels are first Chanels, then Storehouses, and lastly the last Emissaries of the animal Spirits. If it should be demanded, for what end so great plenty of Spirits should be designed for these ignobler parts; I say, that this is done for the performing the acts of Motion and Sense there, which are highly necessary for the preserving of life it self. For although local motion, which is always performed by the help of a Muscle, as of a Spring, is not convenient for the Viscera of the lower Belly; yet intestine motions are brought forth by them almost continually, and after many fashions: viz. for the subduing the Chyle, also for the separation of some parts and particles from others, both of that, and also of the bloody Liquor, and the protrusion of every one towards their designed bounds, the Fibres and nervous shoots reaching into the Membranes of the Viscera and the Coats of the Vessels, yea and into the textures of the Parenchyma, are variously drawn together, to wit, these are pulled upwards, those downwards; sometimes many together, sometimes apart or succes∣sively, are wont to be drawn hither and thither. In truth, it is a sign of the indiscontinued action of these Viscera, that as well in sleep, and perhaps more than in waking, the Culinary work of Nutrition is per∣formed; and whilst the Organs of the other Faculties are at rest, there is no quiet granted to these: but that the Mesenterick nerves perpetually grinding in the Mill, are always busied for the preparing the a∣lible humor and the exporting the same towards all parts.

Moreover in these parts, to which the aforesaid Nerves belong, there is found an exquisite feeling no less than a motive Faculty; for whatsoever heterogeneous or hurtful thing, mixed with the Chyle or blood, is brought to any Viscera, presently the Spirits, inhabiting those parts, being warned of the evil, do greatly tumultuate as it were by entring into a Conspiracy, that what is hostile or troublesom they might shut out. But indeed, because the animal Spirits, flowing by the passage of the intercostal nerve to the Intes∣tines and Viscera akin to them, proceed from the Cerebel; therefore the businesfes of either Faculty, to wit, both the sensitive and locomotive, forasmuch as they are performed the Brain unconsulted, and the ani∣mal scarce knowing it, are not so openly taken notice of, and for that reason they are accounted of less than the spontaneous acts of the other parts.

But as to the manner it self or way of the oeconomy whereby the animal Spirits, destinated to the Vis∣cera of the lower Belly, are exercised, we affirm, That plenty of them flow into all the Mesenterick infold∣ings by the passage of the nerves sent from the intercostal pair; where being heaped up to a fulness, as it were in so many Storehouses or places of Receipt, they are kept to be distributed from thence into several parts, as occasion requires. But that the Spirits flow out of these infoldings, not through singular and larger branches, (as is done in the Muscles) but as it were by Troops of Fibres, into their proper tasks, the rea∣son is, because here the business is performed otherwise than in the musculous stock. For where a Muscle is fixed to the part to be moved, its implanted Fibres perform the whole work of Contraction, or of the motive endeavour; but it suffices for the nerve still to convey new supplements of Spirits, and as occasion serves, the Instincts of the Motion to be performed: but in the Membranes and the Viscera, where Muscles are wanting, the nervous Fibres themselves most thickly implanted, and distributed as it were so many little ropes, almost into every part of the subject, perform the business of Traction or drawing by themselves and their own proper endeavour or force partly; and partly solicite or stir up into motion the Fibres implanted in the Viscera disposed after an uncertain order; which they determinate in their action, and moderate or govern them, as it were so many fingers laid upon the strings of a musical Instrument. For although the Membranes and the Viscera themselves are indued with some implanted Fibres; yet these are not, as it is in the Muscles, of one kind and position; but in the same part some are straight, and others oblique or crooked, these tend upwards, those downwards, and others are carried round; so that divers sorts of motions ought to be performed in the same Membrane or Inward, some∣times together, sometimes successively or by turns: wherefore distinct nerves are required, not only for the several series of Fibres, but for all the parts of the subject, to wit, which may stop here a motion begun in that place, and may begin another anew, or may unite one with another. Truly the motion which is per∣formed in the musculous stock seems like the rude and more simple work of some Weaver, where the shuttle being always cast after the same manner, the Woof is laid under the Thread or Yarn: but the mo∣tions of the Intestines and Viscera may be aptly compared to a Texture very much variegated or flourished, for the weaving of whose more artificial substance or making there is made use of many hands to∣gether, or of a Machine diversly turning about, and furnished with more than a thousand sorts of mo∣tions.

Concerning the many Mesenterick Nerves, and Shoots, and nervous Fibres which go out of them by bands, we must consider chiefly these two things: to wit, what may be the office of each of them for the stirring up of motion or sense, either of them, or both together in any part: then secondly, what the communication of either of them may be with other nerves, infoldings or bundles of nerves, by reason of which a Sympathy or consent of actions arises at once in divers parts. According to these two respects we will particularly weigh now the several nervous Vessels belonging to the Viscera of the lower Belly.

Therefore in the left side the supreme Mesenterick branch being presently forked like the figure of the Letter Y, contains in its upper shoot the Stomachical infolding, which is also the Splenetick, and in the other lower the Renal infolding or that belonging to the Reins. Moreover, about

the knot of division it sends forth some shoots to the greatest infolding of the Mesentery, Fig. II. F. G. Hence a reason is plain, wherefore there happens such affinity between the Ventricle and the Spleen, and between the Mesentery and the Reins, so that the very often and familiar Symptom of Vomiting is both in Splenetick, Colical, and Nephritick people: because when a Convulsion is begun in any part or Inward, which the Mesenterick nerve respects, presently other parts, to which the infoldings or shoots of the same nerve belong, are drawn into consent.

From this lower infolding a little bundle of Nerves being carried towards the Stomach, inserts its Fibres partly in its bottom, and partly sends them to meet with other Fibres sent down from the nerve of the Stomach, Fig. II. n. The reason of the former is, That whereas there are many Coats of the Ventricle, and divers series of Fibres are disposed in them, for the actuating all of which with a due influx of animal Spirits, the Stomachical nerves, derived from the wandring pair, are not sufficient; it was fit, that for the outward Court as it were or Precinct of this Inward, to wit, for the outmost bottom of it, some forces of Spirits might be supplied from some strange Kingdom, to wit, from the aforesaid nervous infolding of the Abdomen. Instead of this, Spirits also may slide downwards from the same Stomachical branch through other Fibres sent down, and be sent into this Splenetick infolding. Besides also it is ob∣served, That the adventitious nerves aptly conspire with the former, being of the proper dominion of the Ventricle, and that either are not only inoculated within the confines of the Inward it self, but they run into mutual embraces without it, and as it were joyn hands together.

It seems plain, that the nervous Filaments being carried from the aforesaid infolding to the bottom of the Ventricle, may serve there for the performing the acts of Motion and Sensation: but it doth not so easily appear with what office the other handful of Fibres reaching out from hence into the Spleen is charged (Fig. II. ζ.) because this Inward is said to be destitute wholly of every animal Faculty. When we did elsewhere inquire into the use of the Spleen, we thought good to affirm, That its office was to se∣parate the dregs of the Blood and the acid-saline Particles, and whatsoever were of a more fixed nature, and to concoct them more being received into its own bosom, and to convert them into an acid Ferment; by which being again delivered to the blood through the Veins, a sharpness and an asperity, as also an active or fermentative virtue are gotten for its Latex. Wherefore the whole substance of the Spleen con∣sists of a texture of Fibres in the form of a net; to wit, that the Feculencies of the blood migh be more plentifully received, and contained within its spongy cavities and thick passages. I say therefore, that for the fit preserving and dispensing of the Splenetick Ferment, besides the Arteries which carry matter, and the Veins which continually sup back some portion of the same fermented, there seems to be need of ma∣ny nerves also, which both by pulling the fibrous texture of the Spleen, might cause the melancholick and dark Faeces, laid up in it, to be shaken together, and so by defending it from putrefaction and coagulati∣on, cause it to be imbued with an acid and fermentative nature; and also that those nerves may some∣times draw together and constrain the blood-carrying Vessels, sometimes open and inlarge them; that as occasion serves, the Feculencies of the blood may be sometimes more plentifully, sometimes more sparingly laid aside out of the Arteries into the Spleen; also that more or less of the Ferment, preserved in the Spleen, may be poured out on the blood according to the requirings of the Passions or of the natural Instinct. No Hypochondriack but doth abundantly perceive, that some Splenetick nerves do perform motions; for those great perturbations which are wont to be excited in the left side, as when sometimes Inflations, some∣times constrictions of the inward parts, and sometimes various concussions are perceived with a wandring pain running here and there, they are only Spasms or Convulsions or wrinklings together, with which the nerves of the Spleen are ordinarily affected. Nor do its nerves, taken with a Convulsivon, stir up tu∣mults only in the neighbourhood of the Spleen, but oftentimes further into the Heart it self, yea into the whole Body the effects of their inordinations are carried. I have known an Hypochondriack, who present∣ly upon the Spleen being disturbed, seemed to have his Praecordia, being drawn downwards, to be cruel∣ly prest and bound together; so that being very sad and dejected in his mind, also complaining of an exceeding great straitness and constriction of his Breast, he thought himself almost dead. The cause of which kind of distemper was without doubt, that when many Fibres going out of the Splenetick infold∣ing are united with the other Fibres sent from the farthest end of the wandring pair, it easily happens, that the former, being distempered with the Convulsion, do draw together and pull downwards their yoke∣fellows, and by consequence the Trunk it self of the wandring pair, from which the nerves are sent into the Praecordia: certainly by the Sympraxis or joynt action of either kind of the aforesaid nerves, viz. where∣of these respect the Spleen, those the Praecordia, it is effected, that the Trembling Oppression, and other grievous Distempers of the Heart, as also of the Spleen, so ordinarily happen. Further, forasmuch as the Fermentation of the blood depends on the Spleen, according to the influence of this, that perform its Circulation, sometimes pleasantly, sometimes disturbedly. Whilst the Spleen is at quiet, and free from any perturbation, the blood also is quietly moved in Hypochondriacal persons; but if the same be moved and exercised, (as it is wont to be in any passion or violent motion of the Body, or by a Medicine) presently its nerves being distempered with a Convulsion, shake it more with reiterated contractions; so that the fer∣mentative Feculencies, being shaken out of its bosom, flow back more plentifully into the blood, which cause its Latex presently to be troubled, and as it were muddy, and sharpen it with so great acrimony and mordacity, that it burns and pricks the Brain and Heart like needles; from whence in Splenetick people besides that the Reason is obscured, the affections of the Mind, especially Sadness, Hatred, and Anger are very much increased.

Concerning the Splenetick Nerves, by another conjecture, we are yet brought to believe, that they; besides the exercise of the motive Faculty, do both instil into the Spleen its own humor, which promotes the fermentative virtue of that Inward; and also (because the nerves, as was shewn already, convey the Spirits, and sometimes the humors by either way, viz. forward and backward) the same implanted in the Spleen, do often imbibe from it an acetous or Vinegar-like humor, and as it were Vitriolick, from whose acrimony and notable twitching, they are forced into Convulsions.

But forasmuch as the nervous Infolding respecting the Spleen, communicates more nearly with the Ventricle, Mesentery, Liver, and Kidneys, and more remotely with the Praecordia and other parts placed at a distance; from hence the cause is plain, wherefore not only these several Viscera and parts, by reason of the fault of the Spleen, are folded together; but also on the contrary, why the Spleen being indisposed by any Disease, or trouble raised up in any of those parts, is wont to be disturbed: so it is not altogether for nothing, that the Symptoms every where infesting, the cause of them being unknown, are ascribed ordi∣narily to the Spleen; because it fixes not only its own inordinations in other parts, but also suffers for their peculiar faults: which notwithstanding is wrongfully ascribed to Vapours transmitted from this or that part, when the formal reason of every Distemper of this kind for the most part consists in the com∣munication made through the Nerves.

The lower Infolding of the left side seems to be made for the Kidney placed near, into which chiefly the bundle of its Fibres is carried, Fig. II. 4. γ. γ. Certainly that these nerves, following the emulgent Vessels, do embrace the same, and bind them about with a various and frequent complication; that is so made for that end, that by reason of the Artery being so strained and frequently shaken by the draw∣ings of the nerves, the Serum may the more easily be precipitated from the blood: wherefore it is observ∣ed in very great difficulty or danger, when the mind and all the nerves are strained for fear, that a frequent and more plentiful making of water, and that often painful, is wont to be pro∣voked.

The Renal Infolding receives, besides the Nerve common to it with the upper infolding, another new and peculiar one from the intercostal nerve, or rather that coming between from the spinal Marrow, Fig. II. β. Hence it is, that the Loyns have a great consent with the Reins, and suffer so ordinarily for their Distempers with a grievous and largely diffusive pain. Forasmuch as this infolding communicates with the greatest of the Mesentery, the Colick distemper and the Nephritick are much akin, and it is often dif∣ficult to distinguish their fits one from the other.

The Mesenterick branch in the right side, as well as the left, being forked, contains two infoldings: the upper of these (which we call the Hepatick) sends forth from it self many little bundles of nervous Fibres; the greatest of which being carried towards the Liver, cloaths the Hepatick Artery as it were with a Net made of Fibres, Fig. II. ♂. o. The most Learned Glisson observes, That the Hepatick Artery is bestowed on the Trunks of the Vessels, to wit, of the common Chest, of the bilary Pore, and of the Vena Porta; for the watering of which, and for the actuating them with heat and nourishing Juyce, it carries the arterious Blood; to which notwithstanding for the recarrying, an associate Vein is wholly wanting: wherefore that ought to carry the blood, not with a full and free influx, but by little and little, and al∣ways in a constant measure to those membranaceous parts: for otherwise there had been danger, left from the bloody Latex plentifully rushing forward, for that it could not be still remanded presently through the Veins, an Inflammation •…•…hould be excited, or left from its torrent being transfused beyond its bands, the courses of the other rivers in the Liver should be disturbed. But for that the nerves, like Reins, do bind about the Trunk of the Artery, the inflowing of the blood it self is moderated, and they cause it variously to be dispensed according to the wants of those parts to which it is destinated.

From the Troop of Nerves going out towards the Liver, some bend down into the Pancreas, and others into the Gholidock Vessels, Duodenum, and Pylorus, and sow into them thick series of shoots, Fig. II. π. π. The office of these seems to be, to pull together the excretory passages of those parts, and to shake them for the causing Evacuations of the boiling or turging humors upon occasion. Further, from these Fibres being carried upwards, when many others sent from either Stomachical nerve are united, the reason is plain, why from an hawling or pulling made about the Ventricle, the yellow Bile is drawn out of the Gall∣chest into the Duodenum, which being carried from thence into the Ventricle, by reason of a Convulsion of that same Intestine, is cast up by Vomit: because the Stomachical nerves being irritated by a Medicine, or by any troublesom thing, for the making an Evacuation above, and for that cause drawn from thence upwards, they draw together the nerves belonging to the Liver and the Cholidock Vessels, for that they are tied to them, and bring them into consent with the superior Spasm or Convulsion. Hence it happens, that not only the Stomach being first tired, draws to it self the Bile by its Convulsion, and allures it into its own bosom; but the Bile also of its own accord growing turgid, and so being poured out into the Duodenum, forasmuch as it irritates the nerves of this Intestine, and then by their consent, provokes the nervous Vessels of the Ventricle, it presently induces a cholerick Vomiting.

The Hepatick Infolding communicates with the Splenetick by Fibres going between either, Fig. II. θ. The reason of which seems to be, That when one infolding respects the end or the right extremity of the Ventricle, and another the left; that a consent in either and a joynt action may be made to∣wards the Stomach, both communicate between themselves by nerves, as if Internuntii. Truly it seems to come to pass by the passage of these nerves, that the Hypochondriacal pains oftentimes run from the left side

nto the right; to wit, for that a Spasm or Convulsion begun in the Splenetick infolding, is wont to be carried to the Hepatick.

Between the Hepatick Infolding and the greatest of the Mesentery, many Fibres reaching out by bands, are cast out in the midst, Fig. II. p. p. the office of which is to sustain a certain commerce and Sympathy; to wit, such an one is required, both that the Chyle may be ministred from the Intestines towards the Liver still in due proportion, also that the Bile may opportunely slide out from the Gall-bladder into the Intestines for the provoking of Excretion. For we are of this Opinion, That the Meseraick Veins suck∣ing out a certain portion of the Chyle from the Intestines, immediately transfer it through the region of the Liver into the Vena Cava, whereby the blood in the ascending Trunk of the hollow Vein or Vena Cava, might be freshly imbued with nourishing Juyce; even as in its descending Trunk it is refreshed, the same being poured out through the Thoracical Vessels or those belonging to the Thorax. Wherefore it is needful, that there should be a very strict affinity between these Viscera; and the rather, because the Bile ought to be poured out from the Gall chest to the Intestines, not continually, but for some uses, by occa∣sions and intervals. For the Nerves knowing best the wants of either part, warn them both of their mu∣tual duty, and as occasion serves, stir them into action.

It is observed, That in the right side an ample Nerve is stretched out between the Hepatick and Renal infolding, Fig. II. μ. So that between these infoldings a greater and more immediate consent is had, than between those pairs of the other side. The reason of which doth not easily appear, unless perhaps it should be so made for this end, that when from the Reins, in making of water, there is an endeavour of the serous Excretion, the Pylorus and the Cbolidock Vessels being at once drawn downwards, a protrusion of the Chyle and Faeces might be provoked towards the lower parts of the Belly. Certainly this connexion of these infoldings is chiefly the cause, why oftentimes most cruel Vomiting uses to come upon a Fit of the Stone; and that from such a Vomiting the Cholidock Vessels are very much emptied, as if provoked by taking an Emetick.

The greatest Infolding of the Mesentery being placed in the midst of the rest, like the Sun, disperses e∣very where round about nervous Fibres like rays, Fig. 11. ☉. and casts them not only on every one of those infoldings, as if so many Planets with a peculiar Aspect, or Actinobolism or Irradiation, but also it distributes them into many Intestines, sanguiserous Vessels, and other parts lying round about: without doubt upon these nervous Filaments, which are carried from this infolding to the Intestines, as Lines from the Centre to the Circumference, every action of the Intestines, and especially the Peristaltick moti∣on of the Vermiculation, depends; namely for that these Fibres do move successively, and still move fur∣ther every begun action, as it were with a spiral or Screw-like progress.

That from this Infolding many Fibres and shoots going forth, are inserted into the Trunk of the Aorta nigh its descending, and that these reaching towards the Intestines, accompany the Blood-carrying Ves∣sels, and in several places climb over them; from hence it may be inferred, That nerves also in the Abdomen are like Bridles and Reins cast on the sanguiferous Vessels, which either by straining or pulling them together, may sometimes retard, sometimes incite the course of the blood according to the needs of the lower Viscera.

From the greatest Infolding of the Mesentery some noted Fibres and shoots are sent out into the Glan∣dula's of the Womb or the Womens Testicles, Fig. 11. τ. τ. Into which also other shoots from the Trunk of the intercostal Nerve, ibid. v. v. and others going out of the nerve which comes between this infolding and the lowest of the Abdomen, do come together, ibid. 〈☐☐〉〈☐☐〉. So that a provision of Spirits is carried in∣to those parts from a threefold Store-house; which indeed is much larger than is done in the other Sex, when we find scarce any nerve to belong to mens Testicles. Indeed the Womb, besides that it is a very sensible part, ought also to be moved diversly, and in bringing forth a child very strongly: wherefore there are granted to this both more strong implanted Fibres, and also Nerves of a various kind and original.

Most of the Infoldings of the Abdomen, but especially the lowest, and that related to it the greatest of the Mesentery, are oftentimes affected in the Passions commonly called Hysterical, as shall be presently de∣clared. Therefore if at any time such distempers proceed from the Womb, the cause is manifest wherefore the aforesaid infoldings are drawn into consent. But we have elsewhere shewn, That those Passipns are merely convulsive, and not seldom excited without any fault in the Womb. Further, that Symptom very frequent in those kind of Fits, to wit, in which as it were a Globe is perceived to be carried from the bottom of the Belly, and about the Navel to leap out impetuously, which therefore is thought to be an ascent of the Womb; I say, that it is nothing else than most cruel Convulsions of these infoldings. In∣deed oftentimes in Women, and sometimes also in Men, I have known when the convul•…•…ive Affection hath invaded, that a bulk in the Hypogastrium hath been seen to arise, then about the midst of the Ab∣domen so great a swelling to follow, that it could not be hindred or prest down, though strongly attempt∣ed by the hands of a strong man. Without doubt, the cause of this admirable distemper is, that within the nerves of the intercostal pair the in•…•…lowing animal Spirits, as often as they beign disorders or con∣vulsive motions, first (as it is wont to be) begin to grow hot or to be exploded about the extremities of the nerve; to wit, in the lowest infolding of the Abdomen; which affection of theirs, when creeping upwards it is carried to the greatest infolding of the Mesentery, so that the Spirits inhabiting it are taken with the like inordination, it is no wonder, if that swelling up of the middle of the Abdomen, and as it were an explosion of a certain nitrosulphureous matter, should be stirred up. For truly it is not

probable, that that Symptom should be excited from the Womb ascending and being removed from its place, because, besides this part being fixed in its place and firmly established with Ligaments, the bulk of it also in Virgins is so small, scarce exceeding the bigness of a Walnut, that although it should be carried up into the Belly, it could not produce such a swelling. Nor is it more likely, that this sort of distemper is stirred up from the Muscles of the Abdomen taken with a Convul•…•…on: for they, however convulsive, draw together themselves and subjected parts upwards or downwards, or of one side, but they are not able by any means to bear themselves aloft, and to lift up on high, with a force, the region of the Navel. But, as we suppose, the animal Spirits in the greatest infolding of the Mesentery growing fierce, and becoming apt to be exploded, (as such indeed they are whenever they enter into convulsive motions) they being there gathered round thickly into a Globe, do mainly blow up and li•…•…t on high with their effervescency and notable rarefaction that infolding with its whole neighbourhood, and at once drive upward the Viscera lying upon it with a certain vibration or shaking. A more full explication of this Symptom belongs to the Pathology of the brain and Nerves.

In the mean time we shall t•…•…ke notice, that another certain Distemper, viz. the Colical grief doth be∣long to the infoldings of the Abdomen, and especially to this greatest of the Mesentery. For it may be thought, that the most cruel torments that are wont to be excited in this disease do come, not from an excrementitious matter shut up in the cavities of the Intestines, nor always from a sharp humor impact∣ed in their Coats, but oftner from the nervous Juyce imbued with a certain acrimony, and stagnating within this infolding; from whence, by reason of a consent of this with the infoldings both Hepatick and Splenetick, a frequent and cruel Vomiting comes upon these pains. But these Pathologick Speculations being referred to their places, we will follow what we first of all instituted, the further passage of the in∣tercostal Nerve, by which we are led to the two lesser and lowest Infoldings of the Abdomen.

Below the Mesenterick Nerves, out of which the superior Infoldings are made, either descending inter∣costal Trunk sends forth three or four singular shoots, which are carried into the Ureters, Fig. 11. v. v. The use of these seems to be, to pull together, and to jog or shake those urinary Chanels, that the Serum sepa∣rated in the •…•…eins, may be the more readily drawn out towards the Bladder. Moreover, if at any time a viscous or muddy matter doth stick to the passages of the Ureters, or a more fixed stone doth obstruct their Cavities, they, by the help of the Nerves inserted here and there in their whole tract, being pulled together and wrinkled, may press down and always move forward any bulk or substance staying in the passage.

Nigh the Vertebrae, out of which the Crural Nerves begin to go forward, three distinct branches brought to either intercostal Nerve, are carried from thence into the lowest hollowness of the Belly, where they make the infolding which is the lowest of the Abdomen, Fig. 11. ☽. Φ. Φ. Φ. That here so many nerves, to wit, six large ones joyning together do make but a small infolding, viz. a lesser than is raised higher in a single branch of the nerve; the reason is, because this infolding is like an Inn, where the infolding Spirits dwell no long time, but it receiving them only in their passage, presently commits them to other infoldings placed here and there above, below and of one side, and made for divers offices; for from hence the chief passage, and as it were a broad way, leads to the greatest infolding of the Mesentery; more∣over, from hence nerves, diversly going out, make three other infoldings, which respect the parts and ways by which the several Excretions, to wit, of the Dung, Urine, and Seed are made in the lower Belly.

The first Nerve therefore sent out of this lowest Infolding into the greatest of the Mesentery, a little before it reaches to it, imparts two noted shoots to the Glandula's of the Womb; but in its ascent it ad∣mits four other branches, as it were subsidiary, viz. two on either side from the intercostal pair, Fig. 11. X. so that the nerve here seems to be the chief means of passage of the animal Spirits destinated to the greatest infolding of the Mesentery and to the uterine Glandula's; which passage however is carried into the de∣signed parts, not immediately; but a compass being made, it first goes forward beyond its bound, and at length with a certain going back. The reason of which is, that the motions of all the Intestines, viz. the Vermiculations should be directed downwards towards the straight Intestine, and also that the actions of the Womb should tend thither; therefore'twas fit, that the animal Spirits should be supplied from below whither the motion inclined. For by the like means, this Mesenterick nerve and the two returning nerves, being first carried lower, ascend into their Provinces; to wit, that they may pull together the respective parts toward that bound placed below, as it were to a Pully.

Further, for this end, to wit, that the influence of the Spirits actuating some Intestines, might be de∣rived lower; the other infolding of the Abdomen, to wit, the least, is added immediately to this. Be∣cause upon the Nerves being carried from hence about an inch, there grows a small infolding; out of which, one nerve being sent out into the greatest infolding of the Mesentery, stretches it self under the top of the straight Intestine and part of the Colon. Fig. 11. ☿. α. And another nerve, descending from this in∣folding, is carried under the lowest part of the same straight Intestine, Fig. 11. b. which also, two shoots carried from the infoldings placed in the Pelvis or Bason, meet, Fig. 11. d. d. It will not be hard to de∣clare the uses of this infolding and its nerves: because all those nervous passages are emptied about the offices and motions of the straight Intestine. The ascending nerve directs the Vermiculations of the same straight Intestine, as also of the the lower part of the Colon, and then (the greatest infolding of the Mesen∣tery mediating) of some other Intestines to be made downwards; but the descending nerve, in opposition to the other, drawing the lowest part of the straight Intestine upwards, takes care that the Excrements

being carried towards the Arse-hole, may not slide out suddenly and unexpectedly. Then forasmuch as two nerves from the two infoldings placed within the Bason or Tunnel, (which infoldings immediately admitting a noted Vertebral branch, are partakers of the spontaneous Function) meet with this descend∣ing nerve, and are ingraffed into it; it comes to pass from all of them together, that the Excrements being detained at the doors, when it shall be convenient, the Appetite commanding are cast out. Nature, that it might shun filthiness, is so careful, that for the carrying out of the Excrements it constitutes nervous Ves∣sels, with as noted a provision, as for the performing any where of the most splendid offices.

From the lowest Infolding of the Abdomen, two nerves being sent into the Tunnel, receive there on both sides a noted Vertebral Nerve; and so constitute two infoldings, to wit, one in either side, Fig. 11. CC. KK. These infoldings near the doors, placed before the chief excretory passages, serve for the open∣ing and shutting them: a Vertebral branch comes to either as a supply; by which it comes to pass, that besides the increasing the forces of the Spirits, their acts flowing from these infoldings, become in some measure spontaneous. By what means and for what end, the nerve ascending from either infolding, is be∣stowed on the straight Intestine, was shewn but now. Moreover, two descending on both sides, are carri∣ed into the neck or porch of the Womb, Fig. 11. e. g. Without doubt, whatever of sense or motion is made about the Venereal acts, is owed to the influence of the Spirits through these Nerves. In Men the de∣lightful provision of the Genital humor, and in Women the no less pleasant reception of the same de∣pends on the action of those nerves. Lastly, from the same infolding another nerve descending and broken into certain shoots, is distributed on both sides into the Bladder and its Sphincter, Fig. 11. f. Certainly by these nerves the business of making water is performed, and when at any time the same is painful, the troublesom sense is impressed on them. But forasmuch as the nerves dedicated to the several Excretions proceed on both sides from the same infolding, therefore the acts of them all are in some measure alike among themselves, so indeed, that if any excretory passage should be weak or ill affected, it sends forth its charge which it should keep, whether it will or no. This is so well known, that there is no need to illus∣trate the matter with instances.

These Nerves and Infoldings being so made, there is not much business besides left for the intercostal pair. About the beginning of the Ossacrum, both Trunks inclining mutually one to the other, communi∣cate among themselves by a cross shoot, or two, then they end in very small Fibres, which are distributed into the Sphincter of the Anus, Fig. 11. q. r. s. Here the intercostal pair is after the same manner, as we have observed concerning the wandring pair; to wit, either nerve being brought to the end of its course, before they enter upon their last task, incline themselves to mutual embraces. Concerning the last offices of either pair, this Conformity may be also noted; that whenas the Viscera dedicated to Chylisication, to wit, the Ventricle and Intestines, are still continued to the last by the same passage and the same perpe∣tual cavity or hollowness; the first doors of this Cavity, to wit, the Orifices of the Ventricle, are kept by the lowest branches of the wandring pair joyned among themselves; but before the last door of the same, to wit, the Sphincter of the Anus, the extremities of the intecostal pair, also before joyned among themselves, are placed. But to this part, as if it had never provided enough for it, besides the nerves sent hither from either infolding next above, and these extreme productions of the intercostal pair bestowed on it, a branch also and certain fibres from the Vertebral nerve are inserted, Fig. 11. i. k. By the access of which it comes to pass, that the shutting and opening of this door-keeping Muscle becomes spontaneous. Truly many nerves, and those of a diverse kind, are distributed into the Sphincter of the Anus, to wit, because the nutritious Juyce and its stinking recrements, like a certain Chymical matter, are digested within the Intestines, as it were within a Matrice; therefore Nature, which best understands Chymistry, is very careful about the well-stopping the mouths of the Vessels.

From the same Nerve, viz. the last Vertebral, out of which a branch disperses fibres into the Sphincter of the Anus, two other Nerves proceed, which are carried into the Yard, Fig. 11. l. m. The greater of these, which is very large and long, is distributed into the nervous Body of it; the other lesser, into its Muscles. This member, because it receives nerves only from the spinal Marrow, according to our Hypo∣thesis, ought to swell up and to be moved only at the spontaneous pleasure of the will: but that often∣times, by reason of the swelling up of the Genital seed or humor, it is erected and blown up with Spirit, whether one will or no, that is caused chiefly for this reason, Because from this Vertebral pair from whence the nerves of the Yard arise, a nervous process is stretched out into the Vertebral pair next above it: in which the infolding, placed in the Tunnel, imparting nerves to the Prostate, is radicated, Fig. 11. I. K. into which infolding also a noted nerve from the intercostal pair is implanted. When therefore a communication is had between the Prostate, which depend much on the intercost Nerves and the Yard, (by reason of the roots of either being joyned together by the nervous process) it comes to pass, that the action of this follows the affection of those parts; but those parts, viz. the Prostatae, are apt to be moved, not only by the turgescency of the Seed, but also by the passage of the intercostal Nerve are wont to be irritated with too unseasonable an action, according to the impressions made by the Senses or the Brian; into the consent of which presently the Yard is excited.

Concerning the Nerves which belong to the Testicles, here is not much to be spoken; for we have often sought in vain for a great company of nervous passages in them: I have very diligently searched some∣times in Man, also in a Fox, Dog, Calf, and likewise in a Boar and Monkey, but could never find be∣longing to them but one nerve carried from the Vertebral pair, which also for the most part is bestowed on

the Cremasteral Muscle, Fig. 11. M. so that, although an excellent humor is prepared within those parts, yet it doth not easily appear, that its matter is derived thither through the nerves; for we think the Genital humor is no more dispensed by the nerves than the nutritious. For truly it seems, that the Arte∣ries instil a spirituous liquor into the Testicles after the same manner as in the Brain; wherefore in their neighbourhood these sanguiferous Vessels being very much divaricated or spread abroad, are turned about into little serpentine chanels, whereby they subtilize the humor destinated to the Testicles, and infinuate it, having put off all thickness and Feculency, and being truly sublimated, into their substance; because there, as within the Cortex of the Brain, the spirituous liquor being imbued with a volatile Salt implant∣ed in the part, passes into the most noble Clyssus, viz. the Genital humor. But here is not a place to dis∣course more largely of the nature and origine of the Seed: yet because it is commonly objected, That the Seed is made of the nervous Juyce and plenty of Spirits fetched from the Brain, and therefore a large ex∣pence of it doth induce quickly on the Brain and Nerves a great debility and enervation; I say, this comes to pass, because after great profusions of the Seed, for the restauration of the same humor, (of which Nature is more solicitous than for the benefit of the individual) presently greater Tributes of the spiritu∣ous Liquor are required from the blood to be laid up into the Testicles: wherefore the Brain is made languid, being defrauded of its due stock and afflux of the same spirituous liquor; and the Spirits influ∣encing it and the nervous System, because they are deficient in the Fountain it self, are very much depau∣perated and become flagging. Besides we may add, That the animal Spirits also which actuate the Prostate coming from the spinal Marrow, are consumed about the Venereal acts very much; so that the Loyns are also enervated for this reason.

CHAP. XXVIII. Of the Spinal Nerve an Accessory of the wandring Pair; also of the Nerve of the Diaphragma.

AFter we have unfolded the Nerves of the wandring and intercostal pair, which being Executers of the involuntary Function, are stretched out to the Praecordia and all the Viscera of the mid∣dle and lower Belly, and also to some other parts: Next to these follow some other Nerves communicating with the aforesaid in the beginning, or in the exercise of the same office, viz. the spinal Nerve and the Nerve of the Diaphragma; of which we will speak in order.

We have already shewn, that the Nerve of the wandring pair in the beginning is made up of numerous Fibres: to which is joyned another noted Nerve arising from afar, and being ingraffed with them, goes forth together with them out of the Skull. Concerning this Nerve, because the beginning and distributi∣on of it being very irregular, have not as yet been noted by other Anatomists, it may seem worth our la∣bour to make a little more diligent inquiry. Therefore if we would search into the beginning of this nerve, that is found beginning with a sharp point in the side of the spinal Marrow nigh the sixth or seventh Vertebrae of the Neck, Fig. 12. C. C. But being increased in its ascent, is no where inserted into the medullar Trunk, but in its whole tract on both sides lean on its side, to which it is knit by certain admitted Fibres towards the superficies. This arising up from the Neck after this manner, and being carried within the Skull, is joyned to the Fibres of the wandring pair, and is ingraffed with them seeming to grow together into one Trunk, and goes out with them at the same hole from the Skull; which being passed through, the spinal Nerve presently departing from the Trunk of the wandring pair, is at length reflected outward, Fig. 9. ♀. ♂. This stranger or travelling nerve after a short commerce having left his companion, is carried upon the Muscles of the Neck, to which it imparts some shoots, and is inoculated with a certain shoot of the tenth pair; but from thence being carried on further, it goes alone by a long passage, till it comes to the Scapular Muscle, on which it is almost wholly bestowed, Fig. 9. ☽. This nerve is found constantly, not only in Man and four-footed Beasts, but also in Fowls and Fishes; and in these it seems to be destinated instead of Arms, and for the moving of their wings and fins.

Concerning the use of this Nerve, and the reason of its irregular beginning, we shall conjecture after this manner: Forasmuch as that is destinated for the performing the motions of the Muscles belonging to the Arms and Neck, therefore it ought to arise out of the spinal Marrow: but that it is not carried by a direct and near way into its Province, but being carried about by a long compass before it enters upon its task, communicates in its beginning with the nerve of the wandring pair; certainly this seems to be done, to the end that this Spinal nerve, being carried into the parts of the wandring pair, might perform the acts of the Function only involuntary. And indeed it may be observed, That besides the spontaneous motions wherewith the Neck and Arms are wont to be imployed with the previous intention of doing this or that thing, those parts also, before any other member, are affected with pathetick and sudden moti∣ons

according to the force of the Passions, the animal not being conscious of it. For almost all living Creatures do not only turn about their necks at any noise to behold whatever might cause fear; but they being any ways affrighted, in the twinkling of an eye fly away, their feet, wings, fins, or other part an∣swerable to them, being set into a rapid motion. The Neck and the Arms are pliable or observant, not only to fear, but in like manner to the other Passions. For brute Animals, as well as Man, being puf∣fed up with pride or anger, (as we have elsewhere intimated) have their Necks swollen, and their Crests lift up: But as to Man, his hands and Arms are so obsequious to the Passions, and almost to all the conceptions of the Brain, that they are continually agitated in the doing of any other thing with vari∣ous gestures, whereof we are ignorant or not willing them: we scarcely think or speak any thing but at the same time the hands are flung out here and there; and whilst the Tongue hesitates or sticks, or the words as it were stick between the Jaws, the right hand is exercised, as if by its gesture it were en∣deavouring to draw out more swiftly the sense of the mind. Truly that these parts, to wit, the Hands and Arms, do so nearly conspire with the Affections of the Brain and Heart in their motions in some measure in all living Creatures, but more eminently in Man, the cause seems to be this nerv's coming from the spinal Marrow to the beginning of the wandring pair, and communicating with its nerves, and receiving from them as it were the note or private mark of the involuntary Function.

So much for the spinal Nerve, which also like a shrub, growing from other shrubs, hath no peculiar origine, but having received various fibres, is radicated for the greatest part in the spinal Marrow, and (as hath been shewn) partly in the nerve of the wandring pair. Concerning the nerve of the Diaphrag∣ma, of which we shall speak next) many things occur no less worthy remarking. As to its beginning, it may be observed, That it arises from the brachial nerves with a double or triple root; to wit, two or three shoots going out of the aforesaid nerves, grow together into the same Trunk, which is the nerve of the Diaphragma. In man its first shoot, which is also the greatest, is produced out of the second Verte∣bral nerve; and when the first brachial nerve arises from the same handful of Vertebral nerves going out at this place, the aforesaid shoot is rooted in its origine: wherefore, when in Brutes the first brachial nerve arises from the fourth or fifth Vertebral, the nerve of the Diaphragma also begins its rise far lower: two other shoots arise out of the same stocks of the brachial nerves which follow next, Fig. 9. γ Φ. But the Trunk which is made out of these shoots goes forward single through the passage of the Neck and the cavity of the Thorax without any branching forth, even to the Diaphragma, Fig. 9. χ. where being at last stretched out into three or four shoots, it is inserted on either side to the fleshy or musculous part of it: so that, because the Diaphragma is a Muscle, and performs both its motions, to wit, Systole and Diastole by its own Fibres, the office of either nerve is only to carry bands or forces of animal Spirits requisite for the indiscontinued action of that part, and also to convey thither the Instincts of the Motions variously to be performed.

As to the first use of this Nerve, viz. for the passage of the animal Spirits, the business is performed in this Muscle, as it is in the Heart. The Spirits flowing into the Diaphragma by the nerves, receive subsidiary Forces, to wit, a sulphureous Copula from the blood, upon whose explosion being still iterat∣ed by turns, and the receiving of new, the action of this perpetual moveable depends. Concerning the Instincts of the Motions transmitted by the passage of this double nerve, we may observe, That they are, especially in man, of a double kind: viz. either the action of the Diaphragma merely natural for the performing of Respiration, is continually reciprocated according to the uses of the Heart and Lungs, and altered many ways in their tenour according their needs; or secondly, a certain irregular and unusual motion of the Diaphragma is wont to be excited at the beck of the Appetite, or from the instigations of other parts; for the which, whilst the rest of the Organs of Respiration are compelled to conspire, the act it self of Respiration becomes after a various manner interrupted or unequal.

1. As to the first of these, viz. the unforced motion of this Muscle, it may be observed, That the Diaphragma, with the Muscles of the Thorax and the parts of either, conspire in their motion with the action of the Lungs and Heart: and that between all these such a joynt action may be sustained, it is ob∣served, That three or four branches are sent out from the Vertebral nerves, in the branches of which the nerve of the Diaphragma is rooted, into the intercostal infolding, Fig. 9. Θ. and whereas from this in∣folding the nerves are carried into the Muscles of the Thorax, by this means a communication and con∣sent of action is effected between these and the Diaphragma. Therefore the Diaphragma drawing with it self the Muscles of the Thorax, by reason of other nerves, conspires with the Praecordia. These in man going from the intercostal nerve, are already described, and in Brutes from the lower infolding of the wandring pair a nerve is sent down into the infolding of the Thorax, to which besides so many shoots and certainfibres reaching forth into the nerve of the Diaphragma, are instead of such a commerce.

2. The Animal and irregular motions of the Diaphragma proceed from various causes and from the divers instigation of other parts, which also in man become much more signal than in brute Animals; because in him the communication is notable by the nerves reaching out from the Cervical infolding of the intercostal pair into the nerve of the Diaphragma; which kind of infolding and nerves are wanting in Brutes.

As to the Species themselves of irregular motions into which the motion of the Diaphragma is wont to be perverted, it may be observed, That we are able at our pleasure to stop breathing or respiration for some space, and presently to take it or draw it out. In laughing, weeping, and singing sometimes the Systole, sometimes the Diastole becomes stronger, and is made frequenter upward or downward with a repeated shaking; which sort of actions of it are made by reason of those near commerces had between the nerve of the Diaphragma and other respective parts of the Breast and Face; yea indeed from hence it is effected, (as we have already shewn) that man is peculiatly a laughing Creature. Further, (which we have shewn elsewhere) from the Sympathy which happens between the parts of the Mouth and Face with the Diaphragma by those nerves, a good reason of sneezing may be given, and that Problem of Aristotles easily solved, to wit, why men alone, or chiefly before other Creatures, sneeze, For the act of sneezing seems to be made for this end, that man may not only clear his Nose, but that all Torpor or heaviness may be shook off for him from the neighbouring Organs of the Senses, yea and from all the fore-part of the Brain: which thing easily succeeds, if the Membranes and nervous passages besmearing the Nostrils and the Sieve-like Bone, like the holes of a Sponge, being strongly wrung forth or squeezed together, be forced to shed forth their moistures; for these parts so emptied, presently like a pressed Sponge, receive other humors, to wit, those coming from the neighbouring parts. In the mean time, that the watry heap so laid up about the caverns of the Nostrils, may be emptied, it ought to be carried a∣way, or wiped out from thence by a vehement blowing of the Air or breath. Wherefore it is observed, That whilst the inward parts of the Nostrils being very sensible, begin to be wrinkled together from some sharp thing pulling or pricking them, and by that means to draw out the watry humor presently by rea∣son of the passage from thence by the branches of the fifth pair into the intercostal Trunk, and from thence by the passage of the nerves which are extended from its Cervical infolding into the nerve of the Diaphragma, the consent of the same Action or Convulsion is produced even into the cross bound or Midriff; so that by the same Act as it were with which the Nostrils are wrinkled, the Diaphragma also with the Diastole being stronger and longer drawn out, is depressed, that the Breast being dilated as much as may be, the Air may be the more copiously inspired. Then as soon as the Spasm or Convulsion of the Membranes, drawn together within the Nostrils and fore-part of the Head, begins to remit, present∣ly the Midriff leaping back with a force, causes the inspired Air to be violently exploded or drivenout, which strongly wipes away and carries forth with it the humor pressed out within the caverns of the Nostrils.

We yet ought to inquire concerning the Nerve of the Diaphragma, what is the reason, that it always proceeds from the Brachial nerves, and why it doth not rather arise immediately from the spinal Mar∣row. Truly from hence it seems to follow, that the motion of the Arms in some sort respects the acti∣on of the Diaphragma; or on the contrary, that this depends on that. Indeed between these two a cer∣tain respect or habitude happens; which easily appears by this Argument: The Arms or fore-Legs in all Creatures are made for labour and hard exercise; because by the force of these men fight, and perform∣the most hard and laborious things, and Brutes run and ascend the most steep places with great pains. But it is very well known, that by too much labour and over-vehement motion of body, the act of Re∣spiration is very much increased, so that the breath almost fails, and is oftentimes in danger to be lost. The reason of this is, because by great exercise the blood is too much forced into the bosom of the Heart, which, lest it should suffocate it, that it might be emptied into the Lungs, very frequent and difficult Re∣spiration is instituted. Therefore from hence may be inferred, That the exercises of the Body ought to be regulated according to the state of the Praecordia; or that the motion of the Arms should observe the acti∣on of the Diaphragma, viz. lest they being stirred by a violent motion, cause the blood to be driven more into the bosoms of the Heart, than the Diaphragma instituting a most frequent Respiration, can draw from thence into the Lungs. That this Rule may be perpetually observed of all living Creatures it is so pro∣vided, that the nerve of the Diaphragma, chiefly conducing to Respiration, should be tyed, as it were a bridle, to the Brachial nerves, which are the principal in the motion of the Body, and so might time∣ly warn these, if unmindful of their duty, and as soon as breath fails, should command them to desist from further moving the Body. Wherefore we observe, when at any time labouring Cattle are urged beyond their strength in labour or motion, oftentimes either some deadly hurt of the heart follows, or else some uncurable disease of the Diaphragma; for by such immoderate labour, either the Beast lan∣guishing quickly dyes, when it is commonly said, that his heart is broke; or else the tone of the Dia∣phragma being wholly broken, Respiration ever after becomes painful and difficult: which is wont to happen ordinarily to Horses, who are driven into too rapid a course with a full Belly.

CHAP. XXIX. Of the Reason of the difference that happens between the Nerves of the wandring and Intercostal Pair in Man and brute Beasts; also of the other Pairs of the Nerves arising both within the Skull, and from the Spinal Marrow: also something of the Blood-carrying Vessels which belong to the Spinal Marrow.

THus far we have described all the Nerves stretching out to the Praecordia and Viscera, also to most of the other parts, which are the Organs of the involuntary Function, according to the manner by which they are wrought in man; and we have shewn their Offices and uses, and the Reasons of the most noted appearances in all. Before we proceed to the other Conjuga∣tions of the Nerves, it behoves us to shew with what difference the aforesaid Nerves are found in brute Beasts, and for what end such a difference is ordained.

It was already intimated, That the Trunk of the wandring pair in four-footed Beasts doth send forth to the Heart and its Appendix more nervous Vessels than in Man. The reason of which is obvious; be∣cause the Cardiack nerves in Brutes proceed almost only from this pair, and scarce at all from the inter∣costal, wherefore when they are only of one orgination, therefore more are required, all which not∣withstanding are much fewer than the same are in Man from a double stock, viz. being carried from both the Nerves: forasmuch as Beasts want prudence, and are not much obnoxious to various and divers Passions, therefore there was no need that the Spirits should be derived from the Head into the Praecordia by a double passage, viz. that one should be required for the exercise of the vital Function, and the other for the reciprocating impressions of the Affections; but that it may suffice, that all those destinated to every one of their offices, may be carried still in the same path.

In most Brutes the intercostal Nerve goes alone from the Ganglioform infolding of it almost without any branching to its infolding of the Thorax: in which passage however it is not always after the same manner in all; for in some it is carried single and apart from the Trunk of the wandring pair, nor doth it communicate with it in its whole journey, unless a little higher by a shoot sent down from the Ganglio∣form infolding: but in many the intercostal Nerve passes presently from its Ganglioform infolding into the neighbouring infolding of the wandring pair, Fig. 10. C. where, when both nerves seem to close to∣gether, from thence both being involved under the same common inclosure, as it were one Trunk, they are carried together till it comes over against the first Rib, and there an infolding being made, the intercostal nerve, departing from the wandring pair, is carried into the infolding of the Thorax; and the other nerve also is stretched between this and that infolding: which nerves, when one is carried under the other above the Artery of the Chanel-bone, making as it were an handle, straiten its Trunk, Fig 10. g.

Although the intercostal Nerve is carried from the Throat to the top of the Thorax under the same sheath with the Trunk of the wandring pair, yet it is not united to it; but they remain distinct still both of them in the whole tract, and the Membrane being diffected, they easily separate one from the other, unless they be knit together by some fibrils sent from one another in some places: but forasmuch as by this means the intercostal nerve being joyned to the Trunk of the wandring pair, goes under its cover, it seems to be so made only for its safety and better passage: wherefore in some perhaps where the intercostal Trunk is greater, or the course of its passage shorter, where such a safeguard is not needful, it descends alone. We have seen this Nerve covered with the safeguard of the wandring pair of one side, and in the other to have gone out by it self alone.

Whether the intercostal Nerve departs from the lower Infolding of the wandring pair or not, however a branch is stretched out between this infolding and that of the Thorax in many, perhaps in all brute Beasts, which in its passage binds about the Vertebral Artery, whereby the Sympraxis or joynt Action between the Praecordia and the exterior Organs of Respiration is sustained: yea from this lower infolding of the wandring pair sometimes we have observed a shoot and fibres to be carried to the beginning of the Bra∣chial branch, in which the nerve of the Diaphragma is rooted; also sometimes, though rarely, we may have seen some shoots sent from the infolding of the Thorax towards the Heart and its Appendix. In a Monkey above this infolding of the Thorax, as we have intimated before, were some shoots and small branches reaching from the intercostal nerve towards the Praecordia.

We may take notice concerning those Nerves below the Praecordia, distributed every where into the Ventricle and the lower Viscera, that there is scarce any difference of them in Man and Beasts. The nerve of the Diaphragma is placed lower in four-footed beasts: the reason of which is, because the Brachial nerves, out of which that ought to proceed, arise lówer; to wit, because Brutes have longer necks, as if destinated to the yoke. These things being thus premised concerning the difference of the Nerves in ei∣ther Species, it remains that we pass on to the unfolding the remaining pairs of them.

Therefore of those arising within the Skull, the ninth pair is made up of many Fibres also in its begin∣ning, (as was shewed before) out of which being gathered together, one Trunk being made is carried to∣wards the Tongue, through whose whole substance, to wit, from the bottom to the top, having passed, it disperses in its whole passage small shoots on either side, Fig. 9. 〈☐〉〈☐〉. So that nothing is more obvious than that this nerve performs the motions of the Tongue requisite for the articulation of Sounds, as the nerves of the fifth pair spread into this member, serve for the distinguishing of Tastes; for the exercise of either Faculty, viz. both motive and sensitive, the texture of Tongue being notedly fibrous, hath the virtue of a double Organ; therefore by the two nerves, besides the supplements of Spirits, are carried both the In∣stincts of the Motion and the sensible Impressions.

That the aforesaid Nerves of the ninth pair may more easily perform the motions of the Tongue, it sends forth downward one shoot before the entrance of the Tongue, which is united with a shoot from the tenth pair meeting it destinated to the Sternotbyroeidal Muscle; and the other little branch of the ninth Conjugation is distributed into the Muscles of the Bone Hyoides, Fig. 9. θ. θ. In truth these shoots being sent down as so many little ropes, conduce to the moving of the Muscles, which are fixed to the bottom of the Tongue, which Muscles being placed as so many Props to the Tongue, do facilitate its motion.

The Nerve of the tenth pair, although it may seem to arise within the Skull with many little Fibres also, yet being sent down from thence into the bony Cloisters of the Spine, not arising but within the first and second Vertebrae, it is carried without. Presently after its entrance it sends forth two nerves into the infolding of the intercostal nerve; for what end hath been already shewn: But its chief Trunk spreading downwards, and receiving a shoot produced from the ninth pair, is bestowed on the Sternothyroeidal Muscle. Moreover, this nerve reflects branches outwards, which are distributed into the Muscles of the Neck reaching out towards the hinder part of the Head; so this pair, as if it were only of the number or rank of the Vertebral nerves, imparts some branches to the intercostal nerve, and all the other shoots and branches of it serve for the performing of the motions of the Muscles of the Neck, Fig. 9. H. *. □. Δ.

So much for the Nerves arising within the Skull, which (as was shewn) having their being from the parts of the Brain or Cerebel, are destinated to the offices of the spontaneous or the involuntary Functi∣on, and are chiefly distributed into the Organs of the Senses or the Viscera of the vital and natural Facul∣ty. There remain many other Conjugations of Nerves, the roots or beginnings of which consist in the spinal Marrow, which is only the exterior production of the oblong Marrow. These spinal Nerves, be∣sides some branches that they bestow on the intercostal pair, are imployed almost wholly on the muscu∣lous stock, and the office of them is to carry outwardly the forces of the Spirits and the Instincts of the Motions to be performed, and to convey inwardly the impressions of sensible things. Forasmuch as the spinal Marrow seems to be derived from the Brain, and is as it were a broad and high road produced or leading from the same, without any paths or tracts inserted to it from the Cerebel, therefore the animal Spirits flowing within its nerves, do almost wholly execute the Acts of the spontaneous Functi∣on.

To describe all the several pairs of the spinal Nerves, and to rehearse all their branchings, and to un∣fold the uses and actions of them, would be a work of animmense labour and trouble: and as this Neu∣rologie cannot be learned nor understood without an axact knowledge of the Muscles, we may justly here forbear entring upon its particular institution: but it may suffice concerning these nerves and their medul∣lar beginning, that we advertise only in general what things may occur most notable and chiefly worth taking notice of.

As to the Nerves therefore produced out of the spinal Marrow, it may be observed, That in both sides of it, nigh the outward margine or brim, four or five Fibres arise in the superior brim, and as many in the infe•…•…ior: either maniple or handful pass through with distinct Fibres the Pia Mater, or the lowest Coat spinal Marrow, which is as it were the common sheath of them all; but afterwards the Fi∣bres passing through the third Membrane of either margine, (for three cloath the spinal Marrow) they joyn together, and having cloathed themselves with a Coat gotten from the second Membrane, they be∣come as it were one Trunk; which Trunk going out at the space between the knot of the Vertebre, is again divided into many nerves destinated to several parts. After this manner in the whole tract of the spinal Marrow, the Vertebral nerves have their birth; but in those places where the Brachial and the Crural nerves go out, both the thickness and the breadth of the spinal Marrow are increased, and also the handfuls or 〈◊〉〈◊〉 of the Fibres are larger. All these are well represented in Fig. 12.

The Brachial Nerves are not only far greater than the Vertebrals, so that they appear as it were large and broad nervous chords; but that they may conspire together, and serve for the strong motions of the Arms, or the fore-Legs of Beasts, it is observed, That very many of them are knit together by the cross nervous Processes. These Processes in four-footed Beasts (the fore-Legs of whom are destinated for un∣weariable

pains and difficult labour) are produced cross-ways after a curious manner, as may be discerned, Fig. 10. l. l. The use of these seems to sustain not only the consent of action in many nerves together, but also their mutual strength; that some bands of Spirits might awaken or stir up others, and for the exer∣cising strongly the Iocomotive force, they might mutually support and relleve one another. And not much unlike this, the business is about the Crural Nerves, where nervous cords signally large, being produced from the Junctures of the Vertebrae, whilst they descend towards the Thigh, they which are above receive in their whole tract the nervous Processes which are sent out still from those below, Fig. 11. p. p. p.

We may yet take notice farther concerning the spinal Marrow, that as it sends out Nerves by bands, and as it were by troops, in an orderly series and military order; so its sanguiferous Vessels are disposed with no less signal artifice. For those which are carried in the superficies of the spinal Marrow, and the Arte∣ries, Veins, and other Sanguiducts, which are nigh its compass, do contain some things more rare and highly worth the noting.

In the first place we may observe, That the blood-carrying Vessels do cloath the whole substance or frame of the spinal Marrow, as well as the oblong Marrow with a thick series of shoots; which may be made more manifest to any one, if first of all Ink were injected into the Vertebral Artery; for from such an injection often repeated, it will easily appear, that the infoldings of the Vessels do cover as it were in the shape of a Net, the upper tract of the Marrow. But by what means these Vessels proceed on both sides from the Trunk of the Vertebral Artery, and also the blood-carrying Veins, which are destinated to the whole spinal Marrow, and the inferior portion of its arterious passages, doth not so plainly appear; because the bony Cloisters of the Vertebrae are not broken through without much labour, especially in grown up living Creatures; and in that work the beginnings and branchings out of very many Vessels are wont to be blotted out: But that we might more accurately search into these hid things, we made the dissections of several Embryons, in which we were able to dissect more narrowly into all the recesses of the Bones: fur∣ther, that all the tracts and branchings out of them might be the better perceived in all the Vessels, we did cast in divers coloured Liquors. And we had our desired wish: for presently we found with much ad∣miration, that those kind of Vessels, viz. Arteries, Bosoms, and Veins, which respect the Head, belong also to the spinal Marrow with no less a noted disposition of provision.

When we did dissect the Heads apart from the Spine, we did think, according to the Opinion of the Vulgar, that the Vertebral Arteries did belong only to the Head: and when there did appear in the cut off Trunk of the oblong Marrow three arterious branches (as they are described above in the first and second Table) therefore in the Explication of either Figure we have affirmed the Vertebral Artery to be carried with a triple branch into the hinder part of the Head. But the Vertebral Artery pays to the superior part of the Spine as great Tributes of Blood as to the Head it self; and that middle arterious branch, which is marked in the first Figure with the Letter T, in the second with S, doth not ascend into the Head, but descends from that concourse of Vertebral Arteries towards the Spine, and conveys downwards from the common flowing together of the blood there made by many Arteries, the Latex for the watring top of the spinal Marrow. Wherefore in this place it seems convenient, that we do not only correct that er∣rour of ours, but that we deliver an exact description of all Vessels which are destinated to the Spine, viz. which contain many wonderful things. As therefore these Vessels are of a threefold kind, viz. Arteries, Bosoms, and Veins, we will expose each of them particularly; and first concerning the Arteries we say.

The Arteries which carry the Blood towards the Spine, are disposed after one manner above the Heart, and after another below it. As to the first, whereas the Trunk of the Aorta being there cleft presently into many branches, departs from the Region of the Spine, therefore the Vertebral Artery is produced on both sides from its axillary branches, which ascending straight into the hinder part of the Head, sends forth a branch into the meeting together of every Vertebrae: But below the Heart, forasmuch as the Aorta, in its whole descent, lyeth on the Spine, two Arteries are received into the Spine from its bottom nigh its Internodia or spaces between the knots of the Vertebrae; so that if the Trunk of the Aorta be cut open long-ways, there will appear a series of double holes through its whole tract, after a most curious man∣ner, as in the head of a Lamprey.

The arterious Branches which are carried both above and below the Heart towards the Spine, becom∣ing presently forked, bestow one shoot on the neighbouring Muscles, and another they insert into the Junctures of the Vertebrae; which being carried within the bony den, is cleft presently into three branches, two of which are bestowed on the medullar Trunk, and the other on the Membrane compassing about the bony den before, Tab. 13. Fig. 3. a. b. c. d. e.

As to the shoots destinated to the medullar Trunk, they presently tending two ways, and meeting with either maniple or band of nervous Fibres, ascend towards their beginnings; and so one little Arte∣ry having got to the superficies of the hinder Marrow, distributes into it hairy Vessels: but the other ar∣terious shoot, which is the greater and chiefest, as soon as it attains the margin of the former Marrow, is carried from thence by an oblique passage into the middle fissure or clest of it, where •…•…eeting with a •…•…hoot of the pair of the other side, it is united to the same, and from that joyning together the arterious Trunk, as it were a common passage, and made up of either Vertebral shoot, descends into that cleft by the open space of one of the Vertebrae, and in that short passage both dispenses little Arteries on either

side, and also inserts them leaning on the Pia Mater more deeply betwixt the sides of the Marrow: and so whereas in the whole tract of the Marrow, the chief Trunk of every Artery is carried into the middle cleft, it seems at first sight, as if the same arterious Trunk were carried under the whole substance of the Marrow from the head to the tail, Tab. 13 Fig. 1. Further, as by a concourse of several shoots of either side, the spinal Artery descends above the cleft of the Marrow; so where the Trunks of the Ver∣tebral Arteries joyn together (which happens to be done sometime in the hinder part of the Head above the oblong Marrow, and often in the Neck above the spinal) an arterious branch somewhat bigger than the rest is stretched out downwards. This formerly (as we mentioned but now) we mistook for the third ascending branch of the Vertebral Artery. But I have often taken notice, that in Brutes, where the Vertebral Arteries have met together with an acute Angle above the medullar Trunk, they are presently, departing one from another, stretched out directly to either brim of the Marrow, from whence imme∣diately being bent back, they are carried again into a mutual meeting, so that between their two joyn∣ings together is made the figure Rhomboides, as it is in Tab. 13. Fig. 1. C. The reason of which without doubt is this; to wit, that the more rapid course of the blood going towards the Head might be hin∣dred by its flood being a little space divided.

The third Brancy of either Vertebral Artery being carried into the anterior Cavity of the bony Den, and being presently made forked, tends to the right and left, and is on both sides inoculated to the next shoot of the same side and by the cross process, they of either side are united after the same manner; and so all the Arteries of this cense or rank receive one another mutually, as it were links of a chain, in the whole tract of the Spine, and are continued in the same bending passage. If Ink be cast into the Trunk of the Vertebral Artery and most of the hollownesses of the Aorta, all these Arteries dyed with the same, will appear a pleasant spectale, like Net-work, as may be seen Tab. 13. Fig. 3.

The top of this arterious Infolding being carried into the Skull, inserts two shoots sent forth straight into the wonderful Net, and imparts two others going out side-ways on both sides to the Dura Mater: the lower end of the same reaching to the Os Sacrum, ends in very small Vessels which serve for the Mem∣brane of the Bone.

If it should be asked, For what end these Arteries being concatenated with such frequent ingraffings are disposed within the Back-bone: This seems to be so ordained for three uses: viz. First, These Vessels (as al∣so the passages of the Bosoms) are divaricated after this manner with repeated compassing about, that a constant heat from the blood being so turned about, as it were into frequent Whirlpools, might be sup∣plied about the compass of the spinal Marrow, as it were by a Balneum Mariae; even such a manner of office as the Choroeidal infolding performs within the infolding of the Brain. Secondly, Care is taken by this means, lest the blood destinated for the spinal Marrow, might flow thither too plentifully, or might be defective in its due influx; for the blood being about to flow into the medullar stock plentifully, is di∣verted from the little branches c. d. into these Emissaries e. f. and in its defect the subsidiary provision be∣ing called out of the middle infolding through the chanel e. into the Vessels c. d. is derived into the same medullar Trunk. Thirdly, The use of this arterious infolding seems to be, that the blood may be distri∣buted from its passages into the Membranes, viz. which is carried every where from them through the Capillary Vessels; the reliques of which also are supped back by the little chanels sent out of the bosoms. Further, from this Store-house, if necessity urges, a certain provision is had for the wants of the Brain; wherefore from hence the small Vessels end in the wonderful Net.

So much for the Arteries distributed about the Spine or Back-bone; the Vessels of the second sort are the Bosoms which come between the Arteries and the Veins for the use of the spinal Marrow no less than of the Head it self, and are here ordained with a more curious implication. But the reason why bosoms are required to these more noble parts, and scarce to any in the whole Body besides, is this, to wit, that about these bodies all manner of extravasation, or any stagnation of the blood, might be hindered: but sometimes the Veins are not sufficiently emptied, that they may presently receive from the Arteries the deposited blood, and so may prohibit any flowing out of it; wherefore the bosoms, as more fit receivers, are destinated to that office, for that their receptacles are larger and soon emptied; and for that reason they may more conveniently derive the blood from either medullar substance, lest it should overflow it in the Head or Spine.

As to the Figure of the Vertebral Bosom, its passages being conform to the arterious infolding, are put under it in the whole tract of the Spine: for after a like manner, in either bosom, which is extended with∣in the cavity of the bony Den, from the hinder pair of the Head to the Os Sacrum, there is one receiving Vessel, by whose twofold chanels presently the blood is brought back from either superficies of the Mar∣row into the bosom, and another carrying back, by whose passage the same is exported into the Veins. Moreover, in many Animals (though not in all) the bosoms on either side seem to be knit together upon the knots between the Vertebrae by the cross processes, and so communicate between themselves: either bosom in its top is continuued into the lateral bosoms of the Head; further, from it on both sides a passage lyes open into the Jugular Vein and into the Vertebral, Tab. 13. Fig. 4.

What the use of the aforesaid Bosom is in general was but now intimated; to wit, that the blood de∣posited from the Arteries in the spinal Marrow, might be presently emptied from thence, and be retained within the more large Cavities of the Bosoms, till it may be transferred into the Veins being made more emptied: But the reason of the divers sorts of implications, and the frequent ingraffings which is found

about their little chanels, seems to be, that the blood, if by chance it being plentifully heaped up within some part of the bosom, should there stagnate, or be apt to regurgitate into the Marrow, it might be drawn out by those frequent Emissaries here or there into the middle or opposite side: after a like manner it is with the bosoms about the Spine, as when a Country-man digs his ground frequent cross Furrows for the draining away any superfluous moisture.

There remains another use of the Vertebral Bosoms, of which we made mention before, to wit, that the blood nigh the medullar Body, being brought through their variously intorted Meanders, (like the ar∣terious infoldings) might yield heat requisite for the swift passage of the animal Spirits, as it were a Baln•…•…um Mariae. That the bending tracts and complications of the Bosoms may be the better seen, a certain tincture may be cast into the Vertebral Veins; and presently that invading the passages of the bosoms and marking them, will exhibit the appearance of a long Ladder with many little labels hanging to it.

Yea at length by those little roundles we are led to the third kind of Spinal Vessels, which are the Veins, into which all the bosoms immediately convey their burden, whereby they being continually emp∣tied, may be still able to receive fresh blood: wherefore the venous branch is stretched out by the several joyntings of the Vertebrae into the bosom, which presently carries away the blood laid up in it, and to be reduced towards the Heart. The Veins designed to this office, after the example of the Arteries, are disposed after one manner above the Heart, and after another below it. As to the first, a branch going from the Trunk of the Vena Cava below the Chanel-bone, or the first little Rib of the Breast, accompanies the Vertebral Artery, and ascending by the holes of the Processes between the several Vertebrae, inserts a little branch to the Bosom, Tab. 13. Fig. 2. b. b. b. Then the top of this Vein being carried towards the hinder part of the Head, is continued into the Trunk of the Bosom, and opened by the other passage into the Jugular Vein. But further, as if these communications were not yet sufficient for the draining away the blood, transverse branches also are stretched out between both Veins, Tab. 13. Fig. 2. i. i. i. So manifold diverting places appear, by which it is enough and more than enough provided, lest the blood might flow back towards the medullar Trunk upon any occasion. Below the Heart, because the Trunk of the Vena Cava cannot, as the Aorta, immediately lean upon the Spine,: and carry shoots straight to the same, therefore it sends forth a Vein without a Companion, out of whose Trunk forked or twofold branches being sent forth, go forwards both to the Muscles of both sides and to the Spine it self. Below the Kid∣neys, seeing there is a space granted for the Vena Cana to be carried nigh the Spine, the Azygos Vein ends, and from the Trunk of the greater Vein, as from that of the Artery, the Vessels belonging to the Loyns immediately proceed.

These things being lately observed concerning the blood-carrying Vessels belonging to the Spine and the hinder part of the Head, and here inserted in the place of an Appendix, ought to be referred to the other Doctrine of this kind, delivered above in the eighth Chapter. In the mean time, that we may re∣turn to our purpose, to wit, what remains of Neurologie, there is not much more to be met with worthy note concerning the Nerves: For they, as to the greater and chief Ramifications, are almost constantly both in Man and brute Beasts, after the manner we have described them. Sometime it happens, although very rarely, concerning the divarications of the smallest Shoots and Fibres, that there is some variety: but as to the primary Vessels, and those drawn from them, the Configuration of every pair of Nerves is still the same or alike in all. It now remains, that the Theory of the Nerves, hitherto drawn in words, and so only objected to the Understanding, may also be shewn to the Sense, which will make it clearer. Where∣fore we have taken care, that the ingraven Delineations of the wandring and intercostal pair of Nerves, and also of others which are of chief note, and of the Spinal Marrow it self be plainly exhibited. The Fi∣gures of these, although taken from a dead Example, yet after many Dissections and a frequent compar∣ing them together according to their several parts, they are described as if from the life; the Lineaments of which with Characteristical Notes, that they may be the better and more distinctly perceived, and a large draught of every Figure, equal almost to the Scheme of Nerves in their animated Body, we have caused to be cut: further, because the Contents of either side and of the Cavity between, cannot be at once described in their proper situation; therefore here it is supposed, That the Spine, with the oblong Marrow, or the whole medullar Stock, cut in the midst is rolled out, and both sides of it, with the pairs of the Nerves arising in the whole Tract, is turned outward.