Fig. 2.
The Testes, Vas Deferens, and Vasa Praeparan∣tia Display'd, together with some Lympheducts of the Former.
A, The Arteria Spermatica continued from a Portion of the Descending Trunk of the Arteria Magna: I can't but suspect this Part of the Figure to be Erroneous, since in the many Subjects I have always observ'd the Origin of the Spermatick Artery to be very Small, even much Smaller than its Inferior Trunk; insomuch, that its Ca∣vity Arising from the Arteria Magna, would scarce admit the Smallest Probe commonly us'd, it being but just Capacious enough to receive a Large Hogs Bristle.
a a, &c. The Ramifications of the Spermatick Artery in their Descent to the Testes.
B, The Trunk of the Spermatick Vein with a Portion o•• the Vena Cava, into which it Enters;
C D bb, &c. Its Various Anastomoses and Re∣tiforme Inosculations, as it Ascends from the Te∣stes.
E E, The Valves of the Spermatick Vein which look from below Upwards, and prevent the Descent of the Blood in that Vessel. Should it be askt why the Spermatick Veins in Humane Bodies, and the Arteries in Quadrupedes should have a Tortuous Progress towards the Testicles; and Vice Versa the Humane Spermatick Arteries and Veins of Quadrupedes should pass Straight? We answer, Tho' the Separation of the Semen in the Testicle is after the Manner of that of other Li∣quors in Conglomerate Glands, yet we constantly find in all Animals, that the Arteries of the Testes are Propagated from their Large Trunks at a considerable Distance from them; and those of the Conglomerate Glands, are always supply'd with Blood-Vessels from the next Neighbouring-Branch: And this Practice in Nature we can't at present Account for otherwise, than that the Blood in the Testicles should not pass with that Velocity as it do's in other Glands; else what should be the Design of those many Turnings and Windings made in the Spermatick Arteries of most, if not all Quadrupedes? But that every An∣gle of their Contortions should take off the Im∣petus of the Impell'd Blood from the Heart. But the Subject of our present Animadversions here, offers an Objection. Why than are the Sperma∣tick Arteries in Humane Bodies Straight, when their Progress is towards a Perpendicular Descent, upon the Account of the Erect Position of the Body? We answer, That the Descending Progress of the Blood might be a very good Argument of its Enjoying a freer Accession to the Testes; but we constantly Observe in all Humane Bodies, that the Spermatick Arteries are (as we have Inti∣mated above) very Small at their Originals from the Arteria Magna, which is a sufficient Impe∣diment to any great Impetus of the Blood from the Great Artery: Nor was this Contrivance in Nature necessary in Quadrupedes, because it would be an Impediment in them in providing that Requisite Stock of Semen to Impregnate the Female with her Numbers; or in regard a greater Proportion of Semen was in them necessary on the Account of the Length of the Cornua Uteri, which it must first pass thro', before it can Arrive at the Fallopian Tubes and Ovaria: Whence it is, that the Testes of Quadrupedes are much Larg∣er in Proportion, than the Humane. But why the Humane Spermatick Veins are thus Divided and Inosculated with each other, when those of Qua∣drupedes are Straight and fewer Trunks, is Ac∣countable from their Positions; those of Men being towards a Perpendicular Ascent to convey the refluent Blood; and those of Quadrupedes near Horizontal. From hence the Necessity of making one of these Blood-Vessels Varicous, do's Appear, especially the Humane Spermatick Veins; which, if had the Arteries been also, as in Qua∣drupedes; the Spaces or Perforations in the Mus∣cles of the Abdomen for their Egress, must have been so Large, as that the Intestines would have been continually liable to an Extrusion.
F, Part of the Epididymis.
G, The Glandulous Part of the Testicle De∣vested of its Proper Membrane.
H H, The Vas Deferens partly free'd from the Epididymis, to Exhibit some of its Contortions.
I, The Tunica Vaginalis of the Vas Deferens.
K, The Tunica Albuginea, with some of the Glandulous Part of the Testicle Rais'd with it.
L, Part of the Tunica Elythroides or Vaginalis.
M, Some of the Lympheducts of the Testicle Pinn'd out.