PHYSIOLOGY AND EXPERIMENTAL PATHOLOGY 729 



The appearance presented by the latter strikingly resembled in microscopic 

 appearance the hyperplastic endometrium of early pregnancy. There was 

 generally increased vascularity produced in the whole sexual system. The 

 overdevelopment was apparent even in the muscle coats of the uterus, 

 which were considerably thickened and also more vascular. A somewhat 

 similar change was produced by the feeding of corpus luteum to the 

 female. 



In the male subjects the testes showed a considerably earlier growth 

 and development ; they were completely and permanently descended at an 

 earlier age, and their gross weight was greater than in a control animal. 

 This is evidenced by extremely active spermatogenesis, with formation of 

 spermatozoa, by a moderate increase in the amount of. interstitial tissue, 

 at a time when the control animal was sexually still very immature. All 

 these developmental, structural and functional changes in the sex glands 

 of both the male and female, produced by the feeding of pituitary extract, 

 show an extremely selective and almost specific action of the latter upon 

 the genital system. 



Anterior Lobe Feeding. The feeding of pituitary anterior lobe extract 

 caused increased weight and greater and more vigorous body growth and 

 development over the control. There was similarly an earlier and more 

 active genital development. The fur was harsher and thicker. Loss of 

 weight, enteritis, and nervous manifestations were not observed as in the 

 beginning of whole gland feeding. As compared with the control, the 

 animal fed with anterior lobe for only 40 days showed an early descent 

 of the testes, which were also larger, more vascular and heavier, not 

 absolutely but in proportion to the body weight. The testis was mature 

 at least as early as two and one-half months, after 40 days of anterior lobe 

 feeding. The period of complete sexual development was shortened by at 

 least one month, or about one-third of its normal time. Histologically, the 

 testis at this age was mature; it showed an abnormally early and active 

 karyokinesis, more active in fact than was seen in the testis of a supposedly 

 normal rat at the age of from three to four months. The testis of the 

 control at this same age was quite immature. The interstitial cells did 

 not seem to have increased in number proportionately to the increase in 

 spermatogenic cells and spermatozoa. The epididymis contained more 

 spermatozoa and had a more active-looking structure. The prostate gland, 

 seminal vesicle and vas deferens showed a correspondingly early and 

 increased development and activity. These changes produced by the feed- 

 ing of anterior lobe indicate that the latter supplies the active principle in 

 the whole gland responsible for the changes reported above, following the 

 feeding of whole gland extract. 



After prolonged feeding of anterior lobe extract, over a period of 

 eight or nine months, the sexual instincts were early awakened, along 



