THE PKOSTATE GLAND AS AN ENDOCRIN ORGAN 527 



Experiments with glycerin and aqueous extracts of the prostate gland 

 have been made by Thaon, Posner and others, who found that such extracts 

 are toxic on intravenous injection, producing a powerful rise in blood 

 pressure, which is followed by a secondary fall and a standstill of the 

 heart. More recently, Legueu and Gaillardot made similar experiments 

 with extracts of hypertrophied prostatic glands, and found them to be 

 even more toxic. 



Vishnevski reports that prostatic secretions exert an influence on 

 phagocytosis. 



Perhaps the most convincing argument or evidence in favor of an 

 internal secretion of the prostate is afforded by the observations of the 

 present author concerning the effect of prostate feeding on tadpoles. 



Effect of Prostate Feeding on the Growth and Development of Tad- 

 poles. Gudernatsch was the first to call attention to the remarkable 

 influence exerted by the feeding of thyroid and thymus glands on frog's 

 larvse. That observer noted that feeding of thyroid glands produced a 

 dwarfing or shrinkage in size of tadpoles on the one hand, and a very 

 rapid differentiation or metamorphosis of tadpoles into frogs on the other ; 

 while feeding of thymus glands retarded metamorphosis and at the same 

 time stimulated growth, with the resultant formation of giant tadpoles. 

 These observations have since been confirmed and extended by Rogoff 

 and many other investigators. Gudernatsch and other observers have also 

 studied the effect of feeding of other organs and glands on the development 

 and growth of tadpoles, and have found that the above interesting effect of 

 thyroid feeding was not produced by any other gland. Recently, however, 

 McCord (b) described a similar phenomenon exhibited by tadpoles fed on 

 pineal gland. So far as the present author has been able to ascertain, no 

 experiments concerning the feeding of prostate gland to* tadpoles, or con-' 

 cerning the relation of the prostate to the growth of other animals, are 

 on record. 



In connection with a physiological and pharmacological study of the 

 prostate gland and of prostatic extracts, the present author conducted a 

 series of experiments in feeding various tadpoles with desiccated prostatic 

 substance. Tadpoles of the following amphibia were employed : Rand syl- 

 vatica, Rana, palustris, Rana catesbiana, Bufo lentiginosus and Amblystoma 

 punctata. Experiments on them were begun at different ages, some being 

 used immediately after hatching, others when they were from one day to 

 three weeks old. In every experiment, several tadpoles of exactly the same 

 age and the same species were placed in two vessels. The tadpoles in 

 one vessel were fed prostate; those in the other vessel served as controls. 

 In all experiments the two sets of tadpoles were kept under exactly the 

 same conditions. They were placed in vessels of the same size, containing 

 the same amount of water, and were kept in the same room under the 

 same conditions of temperature and sunlight exposure. Both sets of 



