to be observ'd, that the Lungs consume more Nourishment than any Part of the Bo∣dy, since they are nourish'd only by the purest and most subtil or bilious part of the Blood, as it appears evidently from the Consideration of those Animals who are des••••tute of Lungs; for they may be almost said to live upon nothing. Thus Fishes who have no Lungs are easily fatten'd by a small quantity of Nourishment; and even it seems not improbable that the Kidneys were design'd by Nature for the Evacuation of the Impurities of the Lungs; for Fishes are equally destitute of both these Parts; and usually Horses who are troubl'd some Days with a Flux of Urine, are seiz'd with a Cough by reason of the driness of their Lungs. I thought fit to in∣sert these Remarks for the Information of those who have lean and wasted Horses; for if the Lungs be affected, they will hardly ever be able to fatten 'em, because that Part will consume a considerable part of the Nourishment, which otherwise wou'd have been turn'd to Flesh; and besides, 'tis observ'd that all Pursive Horses stale very much during the Cure, because the Impurities of the Lungs are voided that way. This is a very true and curious Observation, and was never mention'd by any Writer on this Subject, or inserted in any Book, whether French, Italian, German, or Latin.
If we consider the Vessels and other spermatical Parts that enter the Composition of the Lungs, they will appear to be cold and dry. If we take a View of the fleshy, soft, and spongy Substance of the Lungs, they seem to be hot and moist; and if we reflect on their Lightness and aptness for Motion, we can hardly forbear concluding that they are of a cold and moist Nature.
The Lungs are divided into several parts call'd Lobes which surround the Heart, and espe∣cially into two, by a double Membrane, which in Humane Bodies is call'd the Midriff: They are of a spongy Substance, easily dilateable, which sucks in the Air, and ex∣pels it again with some smoaky and fuliginous Vapours, by the two different Motions of Respiration. This Part is fuller of Veins and Arteries than any other Part of the Body, which make it so subject to Inflammations and Obstructions, as the Hu∣mours are either hot and subtil, or thick and heavy.
Pursiveness proceeds from several Causes: Thus, a slight Obstruction in the Lungs, in the Veins, or some of the Arteries, may cause a shortness of Breath, which is cur'd with easie Remedies.
The same Distemper proceeds usually from some Humours stagnating in the Passages of the Lungs, in the Kidneys, or in the Arteries; for the free Circulation of the Blood being stopt, a great quantity of it gathering together in one place, presses the Ducts or Passages of Respiration, and obstructs the Freedom of Breath∣ing: When the Blood is hot and boiling, it quickly degenerates into Putrefaction, and causes a dangerous Inflammation in that Part, which must be allay'd with powerful Coolers.
This Obstruction is usually caus'd by flegmatick and pituitous Humours; and tho' in this Case 'tis not attended with such violent Symptoms, as are produc'd by the other Causes of this Distemper, 'tis very stubborn, and hardly to be conquer'd by the best Medicines; for those slimy and tough Humours cannot easily be loosen'd and separated from the Parts where they stick, and therefore the Cure must be attempted with cutting and attenuating Remedies. And besides, since the Motion of the Blood is obstructed, and that Liquor depriv'd of the Advantage of Venti∣lation, this kind of Pursiveness is quickly accompany'd with a sort of Putrefaction, and some other Symptoms, which seem to proceed from a hot Principle; tho' the Cause of the Disease is rarely of that Nature.
'Tis plain that Pursiveness proceeds from a cold Principle, and yet the Symptoms that attend it seem to denote the heat of the Cause, tho' it be really of an op∣posite Nature; for this Distemper is usually occasion'd by pituitous Humours, and the thick Flegm which stuffs the Passages, and causes a difficulty of Respiration. This may serve to discover the Error of those who turn out their Pursive Hor∣ses to Grass, and are usually much surpriz'd when they take 'em up with an inten∣tion to confine 'em to dry Feeding, to find them shorter-winded then ever; for the cold∣ness of the Grass augments the Flegm, and makes it thicker and heavier, and conse∣quently more apt to obstruct the Motion of the Blood and Air in the Lungs.
If it be objected that Grass has been sometimes observ'd to relieve Pursive Horses; 'tis reasonable to suppose that in such a Case there was an Inflammation occasion'd by a redundancy of Blood, that might be cool'd and allay'd by the coldness of the Grass, which moistening the Lungs, might give some ease to the