I40 CYCLIC CHANGES IV 



the organ of BIDDER. In the testis tubules it acts both on the 

 spermatocytes, which differentiate rapidly, and on the 

 SERTOLI-cells, by freeing strands of sperm on a large scale. 

 The loose, differentiated spermatozoa thereby arrive in the 

 lumen of the vessel, filling at the same time the vasa efferen- 

 tia, the kidney tracts and the vas deferens with sperm. 



Pregnyl, on the other hand, caused differentiation and 

 freeing of spermatozoa only in the testis, but had no effect 

 on the organ of BIDDER (Fig. 94) . 



Two or more factors present in Ambinon, act on the 

 epithelium; one upon the granulosa epithelium and the 

 oocyte; the other on the SERTOLI- and seminal epithelium. 



The growth of the interstitial tissue in the testis which, 

 in view of its origin, may be compared to the theca of a 

 follicle, runs almost parallel with the frequency of corpora 

 lutea in the organ of BIDDER. It reaches its maximum at 

 breeding period and its minimum in summer (Fig. 93 D). 

 It is suggested that the hormone of the interstitial cells 

 influences the sexual characteristics of the male. The corpus 

 luteum hormone stimulates the oviduct as adnex to the 

 female part of the sexual apparatus, and the testis hormone 

 stimxulates the secondary sexual characteristics as adnexa of 

 the male part. 



§ 5. Summary 



To summarize we have concluded that the organ of 

 Bidder, as a potential ovary in the female maintains and 

 prepares the oviduct until the first oviposition. It atrophies, 

 however, as soon as the ovary, together with its pre-ovulation 

 corpora lutea, takes over this function (Fig. 93 B). Some of 

 / the large follicles change into corpora lutea, whose hormone 

 stimulates the wall of the oviduct to secrete the egg-shells. 

 The rest of the follicles mature and ovulate; the eggs are 

 laid, and the calyces remain. 



In the male, the organ of BIDDER, as a potential ovary, 

 and the oviduct do not play an active part in the sexual- 

 endocrine organization; but by virtue of their vestigial struc- 



/ 



