26 CAREY P. Mc-CORD 



When taken during the age of maximum difference, the testes of the 

 experimentaf animals showed relatively large tubules, their lumina. being 

 almost entirely filled with the many layers of spermatogenic cells in all 

 stages of growth. Active spermatogenesis was evident. Interstitial cells 

 were abundant, but could not be distinguished in size or in number from 

 those of the controls. The tubules of the controls were definitely smaller, 

 when exactly similar portions of the testes of each were studied, and the 

 layers of spermatogenic cells in the lumina were fewer by far, than was 

 the case with the experimental animals. Occasionally there were a few 

 mature spermatozoa, but these were rare, and there was much less uni- 

 formity of development, portions of the testes showing tubules in a very 

 immature stage without even a beginning spermatogenesis. 



The microscopic picture in the seminal vesicles of the two sets of ani- 

 mals was far more striking than that of the testes. Here no particular 

 age of maximum difference could be determined except that, earlier than 

 eight weeks of age, the vesicle always appeared immature in the case of 

 both. Beyond this age, there was a rapid change in the experimental 

 animals, manifested by an enlargement of the lumen of the vesicles at the 

 expense of the thickness of their walls. The cells of the lining mucous 

 membrane were seen to increase in height, while in most cases there was 

 an abundant secretion of colloid material completely filling the lumen. 



Results in Females. As regards results in the females, in accordance 

 with the observations of other investigators, no differences could be made 

 out in size or weight of the genital organs, nor was there a demonstrable 

 difference when these tissues were studied under the microscope. As to 

 body weight, it may be said that a similar curve was shown as in the case 

 of males, excluding those which became pregnant, in which case, naturally, 

 a normal rapid increase was evident. 



As to physiological evidence of hastened maturity in the females, the 

 incidence and termination of pregnancy was the only factor which could 

 be reported, and the results were inconclusive, owing to the fact that in 

 most cases the males were sacrificed before the age of full sexual maturity 

 was readied. 



Of the twenty females, in which total pineal extirpation was shown 

 to have been accomplished, three became pregnant, while among the same 

 number of controls there were but two. All three experimental guinea 

 pigs were delivered of their young, ten days or more, before either of 

 their controls, the earliest of the experimental being delivered three 

 weeks before either control. When it is considered that the normal age 

 for guinea pigs to reach sexual maturity is about nine weeks, it will be 

 seen that, in the above instances at least, this period was shortened one- 

 sixth to one-third. 



A series of operations on young rats also was undertaken, and although 

 an epidemic ruined nearly all of the experiments, it was immediately evi- 



