BODY TEMPEEATURE OF MICE 333 



and on the other those for the later date," we find that for the 

 four males the mean figure for January 26 is 0.54° lower than 

 that for the colder days. For the females, on the contrary, the 

 former figure is 0.68° higher than the latter. As in some other 

 cases, our evidence is conflicting. The two figures, if averaged, 

 would very nearly neutralize one another. 



The writer is painfully aware of the insufficiency of the data 

 included in this section. The figures are few and the variability 

 high. Moreover, it has not always been possible to distinguish 

 among the causes which may have been responsible for a given 

 change. About all that we are justified in concluding is that the 

 mice of the warm-room set underwent an appreciable reduction in 

 body temperature when subjected to a greatly lowered atmo- 

 spheric temperature, and that there was probably a tendency 

 for the body temperature to resume its normal level later, even 

 while the atmosphere remained cold. As regards the effect of a 

 considerable rise in the atmospheric temperature, our evidence 

 is conflicting. Among the table 10 individuals, the results from 

 the two sexes were not in harmony, while among the table 11 

 mice, the old and the young animals gave discrepant results. At 

 best, the data cited above merely serve to strengthen the belief, 

 to which we shall be led later, that the effects of even large dif- 

 ferences of atmospheric temperature are relatively slight and 

 inconstant. 



4. Comparison of the temperatures of the two lots of mice, under 

 conditions which were as normal as possible for each 



It is evident that we can fairly compare only male mice with 

 males, and females with females, while among the males, we 

 must separate the older ones from the younger. It was my first 

 intention to further restrict the comparisons so that morning 

 figures should be compared only with morning figures, and after- 

 noon ones with afternoon ones. This intention was abandoned, 

 however, since such a minute subdivision of the comparable groups 

 seemed undesirable. Moreover, as already stated, the greater 



*' Employing only the first figures for the day (thirty-second readings). 



