IOO 



Scientific Proceedings (112). 



ethanol to produce depression, when injected in the form of 4 per 

 cent, solution was about 80 mgs. by weight. 



47 (1629) 



The effect of prostatectomy on the behavior and learning 

 of albino rats. 



By D. I. MACHT and WM. BLOOM. 



[Pharmacological Laboratory, Johns Hopkins University, 

 Baltimore, Md.] 



The prostate gland of the rat is proportionately to the size of 

 the animal much larger than that of man. It can also be com- 

 pletely extirpated with comparative ease. These facts render 

 rats especially suitable as subjects for the inquiry into the question 

 of the internal secretion of that gland. In the present investi- 

 gation an attempt was made to throw light on the relationship 

 between prostatectomy and mental efficiency, the existence of 

 which seems to be supported by some clinical evidence. 



Two series of experiments were conducted on white rats in the 

 circular maze. In the first series of experiments a number of 

 rats were trained to solve the maze problem by finding the way 

 to the center of the maze, by the shortest route, without any 

 errors, and in the shortest period of time. They were then 

 prostatectomized under ether anesthesia, allowed to recover, and 

 their behavior was studied subsequently. Control experiments 

 were made on other rats of the same series and same ages, which 

 were also anesthetized and on which laparotomy was performed 

 but without removal of the prostate. 



In the second series of experiments, young adult male rats 

 were prostatectomized without previous training in the maze, and 

 control laparotomies were also made as before. The animals were 

 allowed to recover and were kept in their cages for periods ranging 

 from 5 to 9 weeks. Then they were trained in the maze and a 

 comparison was made between the learning time of the prostatec- 

 tomized and control rats. 



An analysis of all the data obtained in the two series of experi- 



