THE PROSTATE GLAND AS AN ENDOCRIN ORGAN 529 



Fig. 3. Rana pal- 

 ustris. Feeding of 

 ram's prostate. Note 

 the metamorphosis of 

 the prostate-fed tad- 

 pole as compared with 

 the control. April 20 

 to June 11. 



mander larvae which also take many months before they begin to show 

 signs of metamorphosis, gave definite evidence of a more rapid differentia- 

 tion after feeding with prostatic substance as early as after two weeks, as 

 shown by shrinkage and stumping of the gills and development of fore and 

 hind legs. 



A sufficient number of experiments with controls 

 on various species of amphibians have been conducted 

 to exclude any accidental effects in connection with 

 the above experiments. It seemed to be definitely 

 established that feeding of prostatic substance exerts 

 an influence upon the growth and differentiation of 

 tadpoles. This, of course, would speak in favor of an 

 internal secretion of the prostate gland. It is inter- 

 esting to note that the iodin content of the prostate 

 gland, unlike the thyroid, is but small, and indeed is 

 much less than that of many other glands in the body. 

 It was furthermore interesting to note the differ- 

 ence in the effects of the prostates from the steer 

 and the bull. As will be seen from the illustrations, 



the prostate of the steer was weaker in its action than that of the bull. 

 This is, of course, as might have been expected, inasmuch as the prostate 

 of the steer undergoes more or less atrophy after castration. In a few 

 experiments made in feeding with the human prostate from a case of mild 

 hypertrophy of that gland, the same effects on growth and differentiation 



were noted as those seen after feeding the 

 prostate of the ram (Macht (6), 1920). 



Prostate Feeding to Higher Animals. 

 Following the interesting observations of the 

 growth and development of tadpoles described 

 above, the author undertook the study of the 

 effect, if any, of prostate feeding on some 

 higher animals. This investigation is still in 

 progress. The results obtained so far, how- 

 ever, would seem to indicate that feeding of 

 small quantities of desiccated prostate gland 

 tends to increase the weight more rapidly 

 than normally. Thus, for instance, in two 

 litters of rats of approximately the same age 



and fed on the same diet it was found that the one group of rats which 

 received a small amount of prostate gland substance mixed with its food 

 (1 to 1,000) showed a distinctly greater gain in weight than the other 

 group which received the same ration minus the prostatic substance. Simi- 

 lar observations are in progress on rabbits, kittens and puppies, but the 

 results are still too incomplete for publication. 



Fig. 4. Bufo lentiyinosus. 

 Metamorphosis produced by 

 feeding ram's prostate from 

 May 12 to June 6. Both tad- 

 poles were about a week old at 

 the beginning of the experi- 

 ment. 



