44G AN AMERICAN TEXT- HOOK OF 1'JI YSIOLOGY. 



seminal granules, exist in Bemen. They are possibly parts of nuclei of disin- 

 tegrated cells. < Jomparatively little is known of the composition or the specific 

 function of the individual secretions contributed by the various organs. The 

 disintegration of the nutritive cells of the testis probably furnishes some of the 

 nutritive substance of the liquid. Prostatic secretion is viscid, opalescent, and 

 usually alkaline, and contains L.5 per cent, of solids, comprising mainly pro- 

 teids and salts. It contributes at Least a portion of the substance of Bottcher's 

 crystals to the semen, and their partial decomposition is said to be responsible 

 for the characteristic odor of the seminal fluid. The secretion from the 

 seminal vesicles is fairly abundant, is albuminous, and in some animals at 

 least, Buch as the rodents, seems to contain fibrinogen. This enables the fluid 

 to clol after it- reception in the female passages, and thus to prevent loss of 

 spermatozoa. Camus and Gley 1 find that this coagulation is caused by a 

 specific fermenl present in the prostatic fluid. Cowper's glands secrete a 

 mucous fluid. By careful experiments upon white rats Steinaeh 2 has shown 

 thai removal of the seminal vesicles and the prostate gland, while not dimin- 

 ishing sexual pa— ion and the ability to perform the sexual act, including 

 the actual discharge of spermatozoa, prevents entirely the fertilization of the 

 ova ; removal of the seminal vesicles alone markedly weakens the fertilizing 

 power of the -emeu, ruder normal circumstances the secretions of these 

 accessory glands arc essential to the motility of the spermatozoa, 3 and they 

 may have other important functions. Ivanoh",' however, has been able to 

 impregnate dogs, rabbits, and guinea-pigs artificially by injecting into the 

 vagina spermatozoa taken directly from the epididymis and mixed with a 0.5 

 per cent, solution of .-odium carbonate. 



The Testis. — The testes ( Fig. 219, /) are compound tubular glands with 

 a unique structure. Formed early in embryonic life as solid structures, with 

 the seminiferous tubules (to) represented by solid cords of cells, they remain 

 in the embryonic condition until the time of puberty. Some of the cells, 

 the mother-cells of the -pern 1a t ozoa, t hen begin actively to divide, and the 

 result of division with differentiation is the mature spermatozoa. These 

 latter accumulate at the centre of the tubules, the walls being formed largely 

 of the dividing cells or immature spermatozoa. Other cells do not produce 

 spermatozoa, but seem to disintegrate and give rise to the nutritive fluid and 

 nuclear particles that are found mixed with the sperm-cells. From the time 

 of puberty on, usually throughout life, this cellular activity proceeds, the 

 rate and regularity probably varying greatly with individuals and depend- 

 ing largely on the frequency of discharge of the semen. Spermatozoa may 

 be wanting in old men, but they have been found in individuals at eighty 

 or ninety year- of age. The spermatozoa accumulate within the seminal 



L Camas and Gley: Oomptes rendus de la SocieHS de Biologic, 1896, p. 7*7, and 1897, p. 787. 

 I. Steinaeh: Pfluger'a Archie fiir die gesammte Physiologic, 1894, lvi. ( f. also Rehfisch : 

 V medicinischt Woch L896, xxii. S. 245; and Lode: Sitsungsber. <l. Kais. Akad.d. 



W W ■■■■. Math, naturw. QL, 1895, civ., Abth.iii 



'Cf. Walker: Archivfur Anatomic und Physiologic, Anatomisclier Abtheilung, 1899, S. 313. 

 4 Ivanoff: Journal de Physiologic ei de Pathologic generate, 1900, ii. p. 95. 



