CHAPTER LVIII 

 THE TEMPERATURE OF THE BODY 



MAN, in common with other mammals, belongs to the group of 

 warm-blooded or homothermic animals. In this group the internal 

 temperature of the body, under normal circumstances of life, is kept 

 approximately constant. 



During the katabolic processes of the body heat is constantly 

 evolved, chiefly in the muscles and the glands. It is estimated that, 

 of the 1,700 calories of heat produced per diem by a man of 11 stone 

 when fasting and resting quietly in bed, about 1,200 calories are pro- 

 produced in the muscles, and 500 in the glands. On the other hand, 

 loss of heat is constantly occurring from the surface of the body by 

 radiation and convection, and by the evaporation of sweat. A certain 

 amount of heat is also lost through the lungs. It has been calculated 

 that an adult man in a still atmosphere of medium temperature loses 

 43-7 per cent, of his heat by radiation, 31 per cent, by convection, 

 20-6 per cent, by evaporation of sweat, 1-2 per cent, in warming in- 

 spired air, 1-5 per cent, in warming the food and drink, 1-8 per cent, 

 in performance of external work. These proportions vary with the 

 temperature, as is shown by the following table : 



As the temperature rises the loss by convection and radiation 

 decreases, and that by evaporation rises. 



The Normal Temperature. The normal temperature of man is 

 usually stated to be 98-4 F. This is the temperature as ascertained 

 by taking it in the mouth or axilla. This method is liable to con- 

 siderable error. A more correct idea of the true internal temperature 

 may be obtained by taking the temperature in the rectum, or by passing 

 water and holding the bulb of the thermometer in the stream of urine. 



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