436 



OVULATION IN THE DOMESTIC FOWL 



Assume then A = 175; h is shifted to 7 months and the equation 

 becomes 



log 



175 - X 



= 0.222 it - 7) 



obtaining the following values for x for the White Leghorns. 



The agreement is seen to be excellent except during the first 2 

 months (November and December). The discrepancy during the 

 first 2 months cannot, however, be considered serious, in view of the 

 fact that the initiation of chemical processes even in vitro is in many 

 cases irregular and does not follow the mathematical expressions for 

 the rate of reaction. The initiation of processes in living organisms, 

 especially in the case of ovulation, may be attended in addition by 

 purely mechanical difficulties and irregularities. The discrepancy 

 might also be explained on evolutionary grounds following the argu- 

 ment of Pearl. 5 Pearl calls attention to the fact that the wild Gallus, 

 the ancestor of the domestic fowl, does not lay during the winter 

 months, and that the winter laying period is not a part of the natural 

 or normal reproductive cycle of the hen. The high variability of egg 

 production during this period is explained by Pearl on this basis. 



