TO THAT OF THE BODY. 41 
consequently followed by a rise of internal body temperature; which, 
like the vascular contraction, is greater as the cold is more consider- 
able. Above 70° F. the amount of perspiration varies with the 
degree of heat and so far compensates, by evaporation, for the differ- 
ences of temperature as to maintain the body at a nearly uniform 
The temperature of air at which sweating begins in the nude body 
is not known. It is at about 86° F. when standing at rest. 
