4 Dorothy Price and Richard Pannabecker 



reproductive tracts (equal numbers of male and female) were 

 cultured by the watch-glass method (Fell, 1940) at approximate 

 ages of 15-5, 16-5, 17*5 and 18-5 days post-copulation. The 

 culture period ranged from one to six days with transfer on 

 the second or third day. The tracts were dissected under 

 sterile conditions; the bladder, genital tubercle and, in many 

 cases, the posterior urogenital sinus and urethra were removed. 

 In some categories of explants, one or both testes were also 

 removed by severing the efferent ducts and freeing the testes 

 without cutting the Wolffian ducts. The tracts were then 

 placed on large clots composed of cock plasma and chick 

 embryo extract. This medium had been tested and found to 

 have no stimulating effects on the differentiation of prostate 

 glands explanted from six-day-old rats (Price, 1951, 1953). 

 Some of the foetal explants were subjected to testosterone or 

 oestradiol, which was added to the clots in the form of micro- 

 pellets in saline suspension. The explants were observed daily 

 and the course of persistence or retrogression of the ducts was 

 followed. At termination of the culture period the explants 

 were fixed and studied. This report will be limited to the 

 results on male Wolffian ducts, seminal vesicles and prostate 

 glands. 



The male tracts were explanted in the following categories : 



1) with both testes 



2) with one testis 



3) with one testis which had been detached and replaced 



in position (the second testis was removed) 



4) with no testes 



5) with ovaries replacing the testes 



6) with no gonads; testosterone in the clot 



7) with no gonads; oestradiol in the clot 



Categories 2 and 3 tested whether there was local action 

 from diffusing testis hormone. In addition, category 3 was 

 especially designed to determine whether any observed retro- 

 gression of Wolffian ducts after testis removal was attribut- 

 able to surgical injury or to absence of the testis. 



