Organ Culture Studies of Reproductive Tracts 9 

 that of normal glands at about 19 days (Fig. 2, B, D, G) but 

 no cranial flexures developed. Seminal vesicles w'ere'already 

 developed in tracts explanted at 18+ days. 



A unilateral effect of one testis on seminal vesicle develop- 

 ment was observed. In 26 such explants in which seminal 

 vesicles developed, the glands were larger or present only on 

 the testis side in 20 but were bilateral and equally developed 

 in 5 explants in which the testis was near the gonadless Wolf- 

 fian duct (Fig. 1). 



In explants with no testes or with ovaries, no seminal 

 vesicles developed (16+ and 17+ days) or they remained 

 as at explantation (18+ days). Testosterone stimulated the 

 development of seminal vesicles and was more effective with 

 advancing age of the tract at the time of explantation. As 

 in explants with testes, only the tracts explanted at 17+ days 

 were stimulated to produce well-developed seminal vesicles 

 (Fig. 2, E). Oestradiol stimulated seminal vesicle development 

 in 4 out of 11 explants cultured at 16+ and 17+ days. 



Prostate Glands 



Part of the urogenital sinus region and the urethra were 

 removed from some reproductive tracts at explantation and 

 when the sinus was explanted, it tended to undergo necrosis 

 particularly in the region of Miiller's tubercle. Table I lists 

 the number of well-preserved sinuses and summarizes the 

 occurrence of prostate glands. 



The prostatic buds that developed were from the dorsal and 

 dorsolateral regions and probably represented those parts of 

 the prostate gland complex and possibly the coagulating 

 glands (Fig. 3, B). The removal of the bladder at explantation 

 disturbed the ventral part of the sinus and urethra and, 

 although healing occurred, no prostatic buds were formed 

 from that region. Only one prostate gland (of one or two short 

 buds) developed in explants cultured at 15+ days and that 

 with testes on the tract. At older ages, prostate glands de- 

 veloped in all categories of explants. There was variability in 



