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f,lie production of animal heat. CRAWFORD sta- 

 ted, in consequence of his experiments, that arte- 

 rial blood was possessed of a greater specific heat 

 than the venous, in the proportion of 115 to 100. 

 Taking this statement for granted, it follows, 

 that when the venous blood turns red in the lungs, 

 it must be cooled about 5 degrees, in case it be 

 not heated by the very process which renders it 

 arterial. The ideas, about the distribution of 

 heat, through the body, were at first very vague, 

 and the lungs were considered as a stove, in 

 which the heat was disengaged, and afterwards 

 carried with the blood to all parts of the body. 

 According to CRAWFORD'S idea, it seems as 

 if the arterial blood, in order to maintain the 

 same temperature, as when venous, did exactly 

 want that quantity of heat, vhich is engaged from 

 the air, by the oxygene gas being changed into 

 carbonic acid gas; and when the arterial blood 

 again becomes venous in every part of the body, 

 the retained heat becomes disengaged, and restores 

 what has been Jost by means of transpiration, 

 and by the access of the ambient air, whereby 

 the body always preserves the same degree of 

 heat. If the colouring matter is the principal 

 cause of this, it is easy to perceive, wherefore 

 the body, after abundant losses of blood, is more 



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