Body-Temperature. 119 



was used and simultaneous observations were made of the temperature changes 

 in the rectum and in the well-closed axilla. It was found from this study 

 that there was a strong tendency for the fluctuations in temperature in the two 

 places to be parallel. This preliminary observation, however, needs further 

 substantiation and elaboration, and it is to be hoped that ere long a more 

 complete topographical study of the temperature changes in the body may be 

 made. In the absence of such an investigation it is necessarv to assume that 

 any fluctuations in rectal temperature are accompanied by similar fluctuations 

 throughout the whole body; thus, if the temperature in the rectum falls 1 C, 

 it is assumed that the temperature of the body falls 1 C, although it is known 

 that there are widely varying temperatures in different parts of the bod}''. 



Methods of Obtaining Body-Temperature. 



As ordinarily taken, the body-temperature is recorded by a mercurial ther- 

 mometer, usually under the tongue. It can also be taken in the well-closed 

 axilla, although it has been shown that it requires a considerable period of 

 time to warm the axilla to constant temperature. The body-temperature can 

 also be taken in the rectum. In the private practice of physicians it is cus- 

 tomary to use the sublingual temperature, but for the exact physiological 

 measurements the rectal temperatures are used whenever possible. The diffi- 

 culty in using the ordinary clinical thermometer is that it records but one 

 temperature at a time, and the best study of changes or fluctuations in tempera- 

 ture can not well be made when the thermometer must be continually removed 

 and the mercury shaken down. By means of an electrical-resistance thermom- 

 eter inserted deep into the rectum a large number of studies of body-tempera- 

 ture have been made in this laboratory. These fluctuations have been reported 

 in great detail elsewhere. 1 



With this apparatus the body-temperature can be measured to within 0.01 C. 

 continuously, the thermometer being inserted in the rectum and there allowed 

 to remain, except during defecation. In some experiments this thermometer 

 has been worn continuously for 5 or 6 days. Owing to the flexible nature of 

 the tubing through which the connecting wires are passed, the subject rarely 

 notices the presence of the thermometer a few moments after it has been in- 

 serted. It is assumed, therefore, that records of body-temperature made under 

 these conditions are the nearest normal. This is especially true during sleep, 

 since with the rigid, glass-mercurial thermometer studies during sleep are 

 somewhat abnormal, as the subject is always more or less disturbed by inserting 

 and removing the thermometer. 



1 Benedict and Snell, Loc. cit.; Benedict, Amer. Journ. Physiol., 1904, 11, p. 145. 



