DISCUSSION OF RESULTS. 43 



rubber tubing exactly as for an experiment. They were then immersed in a 

 bath of warm water and readings were taken continuously of the thermal j unc- 

 tion temperature; at the end of 10 minutes, they were withdrawn from the 

 water, the tubing removed, and the clinical thermometer read. In one test, at 

 a temperature of 98 F., the reading of the clinical thermometer agreed exactly 

 with the record obtained with the thermal junction; in a second test, at a 

 temperature of about 99.4 F., the records disagreed by 0.4 F. Shortly after- 

 wards the clinical thermometer used was broken, so that this result could not 

 be verified. 



Although no definite conclusion was reached, these comparison experiments 

 left in the minds of the experimenters grave doubts as to the feasibility of 

 using the mouth in temperature observations, and also an indefinite distrust 

 of the clinical thermometer for accurate work. It should be stated that a 

 type of mercurial thermometer was used that probably represented as good 

 an instrument as is ordinarily available, selection being made from a number 

 of thermometers that had been simultaneously calibrated. It is evident that 

 the rise of mercury in the thread in a series of impulses may easily lead to 

 errors as great as 0.2 F., and hence whatever value the mercury self-register- 

 ing thermometer has to the clinician, it can have little, if any, value when 

 accurate body-temperature measurements are desired. 



ARTIFICIAL CAVITIES. 



In the effort to find favorable places for making temperature observations, 

 certain artificial cavities, such as the closed axilla or groin, or between the 

 closed hands, were carefully studied. These so-called cavities are really 

 more or less exposed portions of the skin, the configuration of which has been 

 changed so as to form a closed pocket. On account of the large amount of 

 subcutaneous fat, greater possibilities for finding such cavities are afforded 

 with women than with men; accordingly, in experiments with a woman 

 attempts were made to study the temperature fluctuations by means of a 

 thermometer placed between the arm and the breast, between the two breasts, 

 and in different parts of the body more or less inclosed by flesh. 



The one great difficulty with all of these so-called artificial cavities is that 

 they require considerable time to warm them to the maximum temperature. 

 The temperature of the exposed skin before the cavity is made may be as low 

 as 32 C, while that in the inclosed cavity, equilibrium having once been 

 established, may be 36 or 37 C. At the beginning of a test, therefore, the 

 cavity will have a temperature not far from 32 C, and will gradually become 

 warmed to 36 C. or thereabouts, before it can be used for comparison with 

 natural cavities, such as the rectum and the vagina. The warming-up period 

 usually occupies 20 or 30 minutes for the axilla, the length of the period 

 depending principally on the closure obtained. For the cavities made by the 

 groin and by the hands, the preliminary warming period is even longer, since 

 these cavities are formed from places ordinarily less inclosed than the axilla. 

 To avoid this loss of time, a hot-water bottle, previously filled with water at 



