BODY TEMPERA TUKE OF MICE 331 



first reading, of 37.14°, the single figures ranging from 35.3° to 

 38 2°. 26 Five hours later, the temperature of two of these mice 

 had fallen considerably, that of the third showing no change. 

 The mean fall for the three was 1.90°. There next followed a 

 considerable rise on the part of all three of these mice, the mean 

 increase, at the time of third test being 1.6° (fig. 2). 



Mar.5 Mar5 Mar. 6 



10AM 3 P.M. "AM. 



Fig. 2 Reduction of body temperature in 5 adult and 3 nearly grown male 

 mice (table 8), resulting from a sudden reduction of 13° to 14° in atmospheric 

 temperature, following the first test. The continuous line represents adults; 

 the dotted line represents the younger lot. 



* 



Of these 8 male mice, accordingly, 6 underwent a net reduction 

 in temperature during the twenty-four hours following the first 

 test, while the mean temperature for the entire lot was 0.42° 

 lower in the last test than in the first. It is also of interest that 

 in the majority of individuals the temperature reduction was con- 

 fined to the interval between the first and second measurements 

 (five hours), while the majority manifested an actual rise between 

 the second and third measurements. ^^ Indeed this rise was very 

 pronounced in all three of the young mice. These last, in com- 

 parison with the older animals, were at first much more seriously 

 affected by the fall of temperature, two of them, indeed, passing 

 far beyond the limits of physiological adaptability. On the other 

 hand, the three which endured the test recovered their normal 

 temperature more nearly in the end. With data so few and 

 variability so high, it would, however, be rash to generalize in 

 this direction. 



Further data regarding the effects of a sudden cooling of the 

 atmosphere upon mice of the warm-room group are to be found 



2^ The mean for all five mice was 36.78°. 



2^ It is true that a rise of 4° to 6° in air temperature occurred during this 

 interval. 



