BODY TEMPERATURE OF MICE 325 



We find a mean fall of 1.56°C., between four o'clock, on the 

 first afternoon and nine o'clock on the following morning. ^^ This 

 is succeeded by a rise of 1.74° during the quarter hour or there- 

 abouts following the first test for the day. The temperature 

 now declines by 1.90°, in two steps, during the ensuing three 

 hours. Finally, there is a rise of 1.58° during the next seven and 

 one-quarter hours, leaving the mean temperature of the five 

 animals 37.84°, or very nearly the same as on the preceding 

 afternoon. 



It will be noted that all of the individuals agree in the charac- 

 ter of the temperature change undergone in a given interval, 

 differing only in the extent of the rise or fall (fig. 1), Such a 

 close agreement in the behavior of a number of individuals, under 

 identical treatment, is not, however, commonly to be met with, 

 as will be realized from an inspection of tables 7 to 12. 



It is likely that several factors are responsible for the tempera- 

 ture changes above revealed. One of these is the condition of 

 excitement due to the temperature tests themselves, or perhaps, 

 rather, a local congest'on, due to the insertion of the thermom- 

 eter. ^^ It is only thus that we can explain the rise of 1.74° 

 during the fifteen or twenty minutes following the first test of 

 April 1. The subsequent fall of 1.90° probably represents merely 

 a return to the previous normal condition, after the excitement 

 has subsided. 



Let us consider for a moment those temperature changes which 

 are due to such excitement or irritation. In many cases, the 

 temperatures of the same mice were taken two or more times in 

 the course of a single day, sometimes after a brief interval, some- 

 times after the lapse of several hours. An analysis of such cases 

 as are contained in the appended tables reveals the following 

 facts: 



1. In those cases where the interval between the first and 

 second temperature tests was less than one hour (twelve to fifty- 

 seven minutes), a mean rise in temperature is shown for both 



'* This despite a rise of 4° in the air temperature. 



" That the rectum was irritated in some cases was shown by the occasional 

 presence of blood on the thermometer. 



