250 THE PHYSIOLOGY OF REPRODUCTION 



activity of the essential organ of reproduction should depend on the 

 presence of an accessory gland of comparatively recent evolutionary 

 development. On the other hand, it is arguable that the prostate 

 may originally have formed part of the testis, and subsequently have 

 become differentiated as a separate organ in the course of phylogeny. 

 Reference may be made in this connection to the somewhat similar 

 theory, which certain gynaecologists have held, that the ovarian 

 functions are dependent on an internal secretion arising in the 

 uterus, whereas the most recent experimental evidence proves clearly 

 that this is not the case (see p. 376). 



According to Lichtenstein l extirpation of the prostate has no 

 influence on the development of the secondary male characters or on 

 sexual desire (cf. Steinach, above). 2 



Griffiths 3 has shown that the prostate glands in the hedgehog 

 and the mole undergo definite cyclical changes which are correlated 

 with changes in the functional activity of the testes (cf. p. 243). In 

 the quiescent state the prostate is composed of a few tubules lined by 

 small, flattened, epithelial cells, which are at this time incapable of 

 producing a secretion. With the approach of the breeding season 

 the tubules grow much larger and the epithelial cells become 

 columnar. During rut the prostate gland is a mass of tortuous 

 tubules, and has grown to eight to ten times the size of the quiescent 

 organ. 4 The tubules are described as being filled with coagulated 

 mucus, containing a number of small round cells resembling leuco- 

 cytes ; while the epithelial cells are said to show numerous mucigenous 

 granules, especially in the inner or lumen half, but also, though less 

 markedly, in the outer half of each cell (cf. de Bonis' description of 

 the dog's prostate referred to above). 5 



The prostatic secretion is expelled into the urethra during the 

 sexual act by the contraction of the sheath of non-striped muscle 

 which surrounds each tubule throughout its entire length. 



It has been shown in both man and animals that the growth of 

 the prostate is dependent upon the growth of the testes, since it 

 remains of small size until the time of puberty, when the generative 

 system reaches its full development. In those abnormal cases in 



1 Lichtenstein, " Untersuchungen iiber die Funktion der Prostate," Zeitsch. 

 f. Urologie, vol. x., 1916. 



2 But cf. Ott and Scott, p. 272 below, footnote at end of chapter. 



3 Griffiths, "Observations on the Function of the Prostate Gland in Man 

 and the Lower Animals," Jour, of Anat. and Phys., vol. xxiv., 1890. 



4 Marshall, loc. cit. 



5 See also Griffiths, " Observations on the Anatomy of the Prostate," Jour, 

 of Anat. and Phys., vol. xxiii., 1889. For the comparative anatomy of the 

 prostate, see Oudemans' Die Accessorise/ten (jleschlechtsdrilsen der Saugethiere, 

 Haarlem, 1892. According to this authority, the hedgehog has two pairs of 

 prostates. The homologies of these glands in Insectivores still seem to be 

 obscure. See below, under Cowper's glands. 





