38 WONDERS OF ORGANIC LIFE. 



as Dr. Prout observes, more than equal to that 

 contained in six pounds of beef. Nor can the 

 generation of this quantity be easily accounted 

 for, even on the supposition that it is owing to 

 the conversion of albuminous matters into gela- 

 tine. A wide field of experiment is here open ; 

 the subject, however, is replete with difficulty. 

 With the function of respiration, according 

 to most physiologists, the maintenance of animal 

 heat is immediately connected. It is a certain 

 fact, that on the union of carbon with oxygen 

 heat is produced ; and, as Dr. Crawford sup- 

 poses, this production takes place from the union 

 of carbon and oxygen in the lungs. Now, 

 according to his theory, arterial blood has a 

 greater capacity for caloric than venous blood ; 

 hence it follows that the heat generated during 

 respiration in the lungs, by the combustion of 

 carbon, is taken up by the arterial blood as 

 rapidly as it is produced, and, consequently, it 

 never becomes sensible, or raises the tempera- 

 ture of those organs above that of other internal 

 portions of the frame. Were it not that the 

 arterial blood was endowed with this capacity 

 for caloric, the lungs would be destroyed or 

 consumed by the combustion going on unceas- 

 ingly within them. It must be acknowledged 

 that arterial blood is sensibly warmer than 

 venous blood, and perhaps the lungs are a 

 shade warmer than other portions of the system. 

 On considering this theory, which has been 

 said to u afford one of the most beautiful speci- 

 mens of the application of physical and chemical 



