340 INTERNAL SECRETIONS 



an acceleration of growth and metamorphosis under the 

 influence of the prostate. He stated further that the prostate 

 gland of the bull is more efficient than that of the ox. Macht 

 and Matsumoto examined the influence of prostatic extracts 

 on different organs such as the bladder, the ureter, the uterus, 

 etc., of rats, guinea pigs and other animals. There was always 

 an increase of tone. None of these experiments supply evi- 

 dence of an endocrine action for this organ. The same may be 

 said about experiments with removal of the prostate; we 

 shall deal with these experiments in the following section. 



2. Simultaneous Removal of the Seminal Vesicles and 

 OF THE Prostate. 



Steinach removed the seminal vesicles together with the 

 prostate from rats about ten months old. Only the lateral 

 lobules were removed, the prostatic tissue surrounding the 

 urethra remaining intact, since removal of this part of the gland 

 causes severe injury to the animal. The sexual behaviour 

 was peculiar for some weeks, but afterwards the operated 

 animals behaved normally. Against these experiments the 

 objection may be made that the prostate was not completely 

 removed, and that the small quantities of prostatic tissue 

 which remained were sufficient to replace functionally the 

 whole prostate in relation to sexual instincts. We shall discuss 

 this question later. 



With rats from which the seminal vesicles and the prostate 

 gland had been removed, Steinach performed breeding ex- 

 periments which lasted about three months. The operated 

 males copulated with normal females as frequently as normal 

 males do. But, nevertheless, not one of all the twelve normal 

 females became pregnant, though spermatozoa were detected 

 in the vagina of the females after coition. 



From these experiments Steinach concluded that by simul- 

 taneous removal of the seminal vesicles and prostate fertiHty 

 is definitely destroyed. Since spermatozoa passed into the 

 vagina, he thought that evidently the functional activity in 

 regard to the power of fertilization of the spermatozoa is 

 influenced by the secretions of the seminal vesicles and prostate. 



But experiments have been performed which do not corrobo- 

 rate this conclusion. Iwanoff induced pregnancy in various 

 mammals by injecting into the female passages a fluid taken 



