THE INCUBATION OF THE EGG 

 Table XXI. 



207 



Hen 



Egg 



13 



14 



104.8105.2 104.5 105.0 

 101. 8'102,2'l02. 0102.5 



15 



105.2 

 102.0 



16 



105.0 

 103.0 



17 



104.6 

 102.4 



In carrying the egg chamber temperature at 102° to 103° 

 the first half and 103° to 104.5° the remainder of the period, 

 Eycleshymer^ observed the temperatures shown in Table 

 XXII. 



Table XXII. 



In this trial, 85 per cent, of the fertile eggs set hatched. 

 Eggs destroyed for the purpose of taking temperatures were 

 not counted. 



Cooling Eggs. — ^The custom of cooling eggs during the 

 period of incubation has arisen from a desire to imitate 

 nature. During the time that a setting hen is away from her 

 nest for the purpose of feeding the eggs become more or 

 less cool. Because this happens in nature it is assumed that 



' Biological Bulletin, May, 1907. 



