EXPERIMENTS OF BICHAT. 551 



existence of those imperfect organizations termed 

 entozoa, which are formed in the brain, liver, 

 muscles, eyes, and other parts of the higher ani- 

 mals, is evident from the fact, that it has no access 

 to them, which is also true in regard to the 

 primordial germs of all animals.* 



That a small proportion of oxygen is ab- 

 sorbed by the blood, and contributes to its for- 

 mation, is highly probable; but I have proved 

 that by far the greater part of it unites imme- 

 diately with carbon and hydrogen in the lungs. 

 If then it be true, that caloric is always dis- 

 engaged during the formation of carbonic acid 

 and water, and that the lungs are the source 



* A decisive proof that the blood of animals is not vitalized by 

 oxidation and decarbonization, is, that during the respiration of 

 plants, carbonic acid is absorbed by the leaves and decomposed, 

 its carbon being retained, and its oxygen returned to the atmo- 

 sphere, the purity of which is thus maintained. Dr. Gilly found 

 that when grass leaves were exposed to the sun in a jar four hours, 

 the following changes were produced : 



At the beginning of the expe- 

 riment, there were in the jar : 



of Nitrogen 10-507 



Carbonic acid 5' 700 

 Oxygen .... 2-793 



19-000 



At the close of the experi- 

 ment, there were in the jar: 

 of Nitrogen .... 



Carbonic acid 



Oxygen .... 



18-667 



But that the circulation of sap, and its conversion into the 

 nutritive fluid of plants, is effected by the agency of solar heat, 

 is evident from the fact, that neither light, electricity, air, water, 

 nor any other physical agent, will produce the phenomena at a 

 low temperature. 



O O 



