File:A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine (1890) (14783206053).jpg

Identifier: textbookofcompar00mill (find matches)
Title: A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine
Year: 1890 (1890s)
Authors: Mills, Wesley, 1847-1915
Subjects: Physiology, Comparative
Publisher: New York, London, D. Appleton and company
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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so that the penis can not be withdrawntill the erection subsides, an advantage, considering that theseminal vesicles are wanting in the dog, as well as Cowpersglands. In the cat tribe there is also an incomplete penialbone. The free poi*tion of the organ is provided with rigidpapillae capable of erection during copulation. As previously explained, the spermatozoa originate in theseminal tubes, from which they find their way to the seminalvesicles or receptacles for semen till required to be discharged.The spermatozoa as they mature are forced on by fresh addi-tions from behind and by the action of the ciliated cells of theepididymis, together with the wave-like (peristaltic) action ofthe vas deferens. Discharge of semen during coitus is effectedby more vigorous peristaltic action of the vas deferens and theseminal vesicles, followed by a similar rhythmical action of thebulbo-cavernosus and ischio-cavernosus muscles, by which thefluid is forcibly ejaculated. 132 COMPARATIVE PHYSIOLOGY.
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PlG. 137.—Generative organs of the mare, isolated and partly opened (Chanvean). 1, 1.ovaries; 2, Si, Fallopian tubes; 3, pavilion of tube, external face; 4, the same, in-ner face, showing opening in the middle; 5, ligament of ovary; o, intact horn ofuterus; ,, a born thrown open; 8, body of uterus, upper face; !), broad ligament;10, cervix, with its mucous folds; 11, cul-de-sac of vagina with its folds of mucousmembrane; 13, urinary meatus and its valve, 14; 15, mucous fold, a vestige of hy-men; 10, interior of vulva; 17, clitoris; 18,18, labia of vulva; 19, inferior commis-sure of vulva. THE DEVELOPMENT OF THE EMBRYO ITSELF. 133 Semen itself, though composed essentially of spermatozoa,is mixed with the secretions of the vas deferens, of the seminalvesicles, of Cowpers glands, and of the prostate. Chemically itis neutral or alkaline in reaction, highly albuminous, and con-tains nuclein, lecithin, cholesterin, fats, and salts. The movements of the male cell, owing to the action of th

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