616 



DR SUTHERLAND SIMPSON ON 



Table VI, 



This shows the Mean Temperature of the Incubating and Control Hens for the 

 twenty-four hours on the 8th, Ibtli, 22nd, and 29th days after the beginning 

 of incubation. 



Day of 

 Incubation. 



8 



15 



22 



29 



A 



40-79 



40-66 



41-42 



41-38 



B 



41-03 



40-91 



40-98 



41-19 



Day of 

 Incubation. 



8 



15 



22 



29 



A' 



41-14 



41-08 



41-07 



41-49 



I 



B' 



41-19 



41-13 



41-13 



41-31 



Day of 

 Incubation. 



4 



11 



18 



25 



A" 



40-78 



40-84 



40-84 



41-49 



B" 



41-26 



41-43 



41-40 



4133 



during the night being associated with the depressant action of the darkness and silence 

 on the bodily tone, in addition to the cessation of the coarser muscular movements. 

 The fact that the temperature of the control is lower in the night than that of the 

 brooding hen, may be explained as the result of the increased depression of function 

 following on the more active condition during the day. 



The curves of k! and B' (fig. 3) correspond more closely than either of the other two 

 pairs, where B' was kept in confinement to some extent, and from this we may conclude 

 that the brooding condition of the hen has no relation to the modified character of the 

 curve apart from its change of habit with regard to muscular activity ; and if one could 

 induce a non-brooding hen to remain quiescent for a similar period, the same result might 

 be obtained. If the temperature of the brooding hen had been uniformly higher or 

 lower than in the control, then it would be necessary to assume the existence of influences 

 other than those which we know to affect directly the body temperature ; but the 

 modification in the temperature curve which does take place, is exactly what one would 

 expect to find in association with the altered habits of the hen. The results, then, point 

 to the conclusion that the diurnal variation in the body temperature is determined by 

 the alternating states of rest and activity. 



