352 FRANCIS B. SUMNER 



5. When we have eliminated these various irrelevant factors, 

 and selected from each group of figures only those which are 

 strictly comparable, we are in position to test the effects of atmo- 

 spheric upon body temperature in the case of animals which have 

 become habituated to widely different temperature conditions. 

 From a consideration of 36 tests, upon 28 adult males, we find 

 a mean difference of at most 0.25° (considerably less, if certain 

 doubtful readings be rejected) between the warm-room and cold- 

 room lots, the figure for the former being the higher. The mean 

 difference of atmospheric temperature during the period of these 

 tests, was 24.5°C. 



For the much smaller number of tests with males three and 

 one-half months old, a mean difference was obtained which is 

 statistically negligible. When the comparisons are restricted to 

 the more reliable figures, indeed, the mean is slightlj^ higher for 

 the cold-room animals. 



Adult females of the warm-room lot gave a mean figure which 

 was 0.76° to 0.95° higher than that for the cold-room lot (depend- 

 ing upon which readings were employed in the computations. 

 See text). These computations are derived from a consideration 

 of 16 temperature tests, made upon 8 individuals. The mean dif- 

 ference of atmospheric temperature to which the two lots were 

 subjected during these tests was 32°C. 



If we seek a single average difference, representing the mean 

 condition of the three groups just considered (for method of com- 

 putation, see p. 337), we find that this lies between 0.16° and 

 0.31°, depending upon which readings are chosen for comparison. 

 The mean difference in air temperature during these thermometer 

 tests was 25°C., which was very much greater than the mean 

 difference between the temperature of two respective rooms for 

 the experimental period as a whole. My methods have thus 

 tended to exaggerate, rather than to minimize, any differences of 

 body temperature which may have obtained throughout the 

 course of my breeding experiments. 



6. Some fairly convincing evidence was obtained pointing to a 

 reduction of body temperature in individuals of either the* warm- 

 room or the cold-room lot, resulting from a very considerable fall 



