It is certain that the cock in coition emits his ' geniture/ commonly called semen, from his sexual parts, although he has no penis, as I maintain ; because his testes and long and ample vasa deferentia are full of this fluid. But whether it issues in jets, with a kind of spirituous briskness and repeatedly as in the hotter viviparous animals, or not, I have not been able to ascertain. But as I do not find any vesiculse containing semen, from which, made brisk and raised into a froth by the spirits, it might be emitted ; nor any penis through whose narrower orifice it might be forcibly ejaculated, and so strike upon the interior of the hen ; and particularly when I see the act of intercourse so rapidly performed between them; I am disposed to believe that the parts of the hen are merely moistened with a very small quantity of seminal fluid, only as much as will adhere to the orifice of the pudenda, and that the prolific fluid is not emitted by any sudden ejaculation ; so that whilst among animals repeated ejaculations take place during the same connection, among birds, which are not delayed with any complexity of venereal apparatus, the same object is effected by repeated con- nections. Animals that are long in connection, copulate rarely ; and this is the case with the swan and ostrich among birds. The cock, therefore, as he cannot stay long in his connections, supplies by dint of repeated treadings the reiterated ejaculations of the single intercourse in other animals ; and as he has neither penis nor glans, still the extremities of the vasa deferentia, inflated with spirits when he treads, become turgid in the manner of a glans penis, and the orifice of the uterus of the hen, compressed by them, her cloaca being exposed for the oc- casion, is anointed with genital fluid, which consequently does not require a penis for its intromission.
We have said, however, that such was the virtue of the semen of the cock, that not only did it render the uterus, the egg in. utero, and the vitelline germ in the ovary, but the whole hen prolific, so that even the germs of vitelli, yet to be produced, were impregnated.
Fabricius has well observed, that the quantity of spermatic fluid contained in the testes and vasa deferentia of the cock was large ; not that the hen requires much to fecundate each of her eggs, but that the cock may have a supply for the large number of hens he serves and for his repeated addresses to them.
