It is well-known that the heat of the body is derived from the 

 combustion of the nutritive materials absorbed ; this combustion 

 takes place mainly in the skeletal muscles and in the muscles and 

 glands of the digestive tract. 



The heat produced by metabolic changes is chiefly absorbed by 

 the blood, an increased quantitj^ of which flows through the heat- 

 producing organ, and with the circulating blood the heat is con- 

 veyed to the other organs of the body. 



The temperature measured in a particular part of the body will 

 therefore depend on the quantity of blood passing through the organ 

 concerned during a given time, and thus not only on the intensity 

 of the metabolism but also on the action of the heart, on the vas- 

 cularity of the tissues concerned, on the state of innervation of the 

 vessels, and further on the conditions for giving off heat to the 

 surroundings and on other purely physical conditions under which 

 the thermometer is placed. 



It is hardly necessary to point out how much the result of a 

 thermometer reading may vary according as one or other of the 

 factors named above exercises a determinative influence in the part 

 concerned. It should be evident that it is only when these condi- 

 tions have been cleared up for each single one of the usually employed 

 local temperatures, that we have a proper basis for the comparison 

 of the temperatures measured, and, on the whole, for judging of the 

 value of a clinical reading of temperature. 



Perusal of the literature dealing with this subject does not, 

 however, convey the impression that the above considerations have 

 been kept in mind in the investigations. In the text-books, for ex- 

 ample, we find standard values for the various local temperatures, 

 but not the limits of variation; in monographs we find purely 

 numerical comparisons between the temperatures of the mouth and 

 rectum; and as a rule the author is satisfied to show a constant or 

 inconstant relation. One is лvarned against taking the temperature 

 of the mouth immediately after a meal; it is an open question whether 



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