104 HEAT OF ORGANISED BODIES. 



the oxygen conveyed by the circulation of the blood to 

 every part of the body, regarded as the source of animal 

 heat ; and, without doubt, it is one great source, 

 although it can scarcely be regarded as the only one.* 



* The most complete exposition of the theory that animal heat 

 is derived from chemical action only, will be found in Animal 

 Chemistry, or Chemistry in its applications .to Physiology and 

 Pathology, by Justus Liebig : translated by Dr. Gregory. The 

 conclusions arrived at by the author, notwithstanding his high 

 and deservedly high position in chemical science, must, however, 

 be received with great caution, many of them being founded on 

 most incorrect premises, and his generalizations being of the most 

 hasty and imperfect character. At page 22 the following passage 

 occurs : " If we were to go naked, like certain savage tribes, or if 

 in hunting or fishing we were exposed to the same degree of cold 

 as the Samoiedes, we should be able, with ease, to consume ten 

 pounds of flesh, and, perhaps, a dozen of tallow candles into the 

 bargain, daily, as warmly clad travellers have related with astonish- 

 ment of these people. We should then also be able to take the 

 same quantity of brandy or train-oil without bad effects, because 

 the carbon and hydrogen of these substances w.ould only suffice to 

 keep up the equilibrium between the external temperature and 

 that of our bodies." 



A brief examination will exhibit the error of this. The analysis 

 of Beef, by D. Lyon Playfair, is as follows : 



Carbon . . . 51*83 



Hydrogen . . . . 7 -5 7 



Nitrogen . . . 15'01 



Oxygen .... 21'37 



Ashes .... 4-23 



And the following has been given by Chevreul as the composition 

 of mutton tallow : 



Carbon . . . . 96 



Hydrogen . .16 



Nitrogen .... 16 



Oxygen .... 48 



About three times the quantity of oxygen to the carbon eaten, is 

 required to convert it into carbonic acid ; hence, the Samoiede, 

 eating more highly carbonized matter, must inspire 288 oz. of 

 oxygen daily, or nearly eight times as much as the " ordinary 

 adult." By the lungs 'he must take into the body 2,304 cubic 

 feet of air besides what will be absorbed by the skin. His 

 respirations must be so much quickened, that at the lowest pos- 



