340 PULMONARY MUCOUS TISSUE. 



The temperature of man is constant : a thermometer, placed 

 in the axilla (armpit), shows it to be always about 37 (C.) ; 

 if we examine the deeper tissues the temperature is found to 

 increase slightly, while in the extremities, which are more 

 exposed, it is somewhat lower. 



In order to keep up the temperature of the body and resist 

 the effects of the surrounding atmosphere, the organism, on 

 the one hand, produces heat, and on the other, possesses 

 powerful means of eliminating any excess of heat. 



It is now proved beyond all doubt that the combustion 

 which takes place in the organism is the source of animal 

 heat : by means of the oxygen furnished by respiration, we 

 consume the carbon and hydrogen of the food received, or 

 of our own tissues (inanition). It is well known that the 

 calorific capacity of carbon is 8000 units of heat, and tha,t of 

 hydrogen 34,000 ; in other words, in passing into the state 

 of carbonic acid or of water, 1 kilog. of the former produces 

 a quantity of heat capable of raising 80 kilogrammes of water 

 from (C.) to 100 (C.), while 1 kilog. of the latter will 

 raise 340 kilogrammes. 



Man, on an average, develops daily a quantity of heat esti- 

 mated at 3250 units. 



Thus, it is seen that we produce a considerable quantity of 

 heat in 24 hours, and that this quantity increases with in- 

 creased activity of nutrition, or when the food is more abun- 

 dant and rich in carbon and hydrogen; the food of the 

 inhabitants of cold countries ought, for this reason, to be 

 richer than that of the inhabitants of the tropical regions, and 

 to contain, especially, a larger proportion of hydro-carbons, 

 without much oxygen, such as the fats which the Laplanders 

 consume in such quantities. 



The heat thus produced serves to keep the body at a tem- 

 perature of 37 (C.), and to raise the fluids, etc., received, to 

 the same temperature. By the aid of a little calculation, 

 joined to what we know of the subject by experiment, we are 



Bernard, " De la Physiologie Ge'nerale." 1872, p. 249.) Legros 

 observed in the dormouse, during hibernation, phenomena which 

 show still more clearly the close resemblance between the cold- 

 blooded and the hibernating animals. Phenomena of redintegra- 

 tion take place in the latter which never occur during their waking 

 hours. For instance, if the tail of the animal in this state be cut 

 off, it will grow again. (See P. Bert, Recherches Experimentales 

 pour servir a PHistoire de la Vitalite propre des Tissus Animaux." 

 1806.) 



