SCIENTIFIC PROCEEDINGS. 



One hundred seventh meeting. 



Abstracts of Communications. 



University and Bellevue Hospital Medical College, April 21, 1920. 

 Vice-President Wallace in the chair. 



77 (1537) 



Effect of underfeeding on ovulation and the cestrous rhythm in 



guinea-pigs. 



By George N. Papanicolaou and Charles R. Stockard. 



[From Cornell University Medical College, New York City.] 



Under well-regulated food conditions the cestrous cycle in the 

 guinea-pig is almost uniformly 16 to 17 days in duration. 



Underfeeding with a diet of 20 grams of carrots per day pro- 

 duces a prolongation of the dices trum and, at the same time, a 

 congestion in the ovary and uterus and a degeneration of develop- 

 ing graafian follicles. 



The extent of prolongation of the dioestrum depends upon the 

 stage at which an animal is underfed. 



Underfeeding during the first 5 to 7 days of the dioestrum has 

 only a slight effect, postponing the next oestrus for one or two 

 days, while underfeeding during the later part of the dioestrum 

 gives much more marked results. 



When an animal is underfed for 5 days, from the 12th to the 

 17th day after an ovulation and oestrus, the next ovulation and 

 oestrus is delayed for about 7 days, being expressed at the 23d to 

 25th day instead of at the 17th. 



Should an animal be underfed for 7 days, from the 10th day to 

 the 17th day after oestrus, the next ovulation and oestrus is post- 

 poned for 10 to 11 days, arriving at the 27th to 28th day, instead 

 of the 17th day. 



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