416 RAYMOND PEARL AND M. R. CURTIS 



and if birds which are ovulating or extruding eggs into the body- 

 cavity continue to digest and absorb the same amount of food 

 as birds in similar periods of reproduction, the birds which are 

 prevented from laying eggs will accumulate reserve energy. 



The experiments so far as they go suggest that birds which 

 resorb yolks or eggs from their body cavity may utilize this 

 resorbed material (and the material not used to complete the 

 eggs) in the production of body fat. There are six cases (1, 

 9, 10, 13, 14 and 15) which show evidence on this point. These 

 birds were all killed for data while in good health except cases 

 1 and 13. Case 1 died as the result of the rupture of an en- 

 larged spleen. Case 13 died from the infection of the body 

 cavity through an abdominal hernia. All these birds had made 

 large gains in body weight since the operation and all were 

 very fat at the time of autopsy. The autopsy records quoted on 

 page 412 show that the unoperated birds which were ovulating 

 into the body cavity and resorbing the yolks were also very fat. 

 The other birds which had ovulated into the body cavity were 

 either killed too soon after the operation to have resorbed 

 many yolks (cases 4 and 8) or died from diseases which might 

 have prevented the accumulation of body fat (cases 7, 12, 16, 

 18, 19 and 26). Some of these cases also had made substantial 

 gains in body weight but they did not appear to be abnormally 

 fat at the time of autopsy. 



Too much weight cannot be placed on the evidence from 

 these experiments, since most of the birds were not fully grown 

 at the time of operation and a part of the gain in body weight is 

 due to normal growth. Further the cases are too few to deter- 

 mine statistically that these birds had accumulated more body 

 fat than laying birds of the same age. This, however, appears to 

 be the case. 



