64- The Chemical Statics of Organised Beings. 



this azote which it has exhaled. in a free state or converted into 

 ammonia? They evidently come from the aliments. 



By studying digestion in this point of view, we have been led 

 to consider it in a manner much more simple than is customary, 

 and which may be summed up in a few words. 



In fact, as soon as it was proved to us that the animal creates 

 no organic matter ; that it merely assimilates or expends it by 

 burning it (en la brulant), there was no occasion to seek in di- 

 gestion all those mysteries which we were quite sure of not 

 finding there. 



Thus, digestion is indeed but a simple function of absorption. 

 The soluble matters pass into the blood, for the most part un- 

 changed ; the insoluble matters reach the chyle, sufficiently di- 

 vided to be taken up by the orifices of the chyliferous vessels. 



Besides, the evident object of digestion is to restore to the 

 blood a matter proper for supplying our respiration with the ten 

 or fifteen grains of coal, or the equivalent of hydrogen, which 

 each of us burns every hour ; and to restore to it the grain of 

 azote which is also hourly exhaled, as well by the lungs or the 

 skin as by the urine. 



Thus the amylaceous matters are changed into gum and 

 sugar ; the saccharine matters are absorbed. 



The fatty matters ai*e divided, and converted into an emul- 

 sion, and thus pass into the vessels, in order to form depots 

 which the blood takes back and burns as it needs. 



The neutral azotated substances, fibrin, albumen, and caseum, 

 which are at first dissolved, and then precipitated, pass into the 

 chyle greatly divided or dissolved anew. 



The animal thus receives and assimilates almost unaltered the 

 azotated neutral substances which it finds ready formed in the 

 animals or plants upon which it feeds ; it receives fatty matters, 

 which come from the same sources ; it receives amylaceous or 

 saccharine matters, which are in the same predicament. 



These three great orders of matters, whose origin always 

 ascends to the plant, become divided into products capable of 

 being assimilated, fibrin, albumen, caseum, fatty bodies which 

 serve to renew or recruit the organs with the combustible pro- 

 ducts, sugar and fatty bodies which respiration consumes. 



The animal therefore assimilates or destroys organic matters 

 ready formed ; it does not create them. 



Digestion introduces into the blood organic matters ready 

 formed ; assimilation employs those which are azotated ; respi- 

 ration burns the others. 



If animals do not possess any peculiar power for producing 

 organic matters, have they at least that special and singular 

 power which has been attributed to them, of producing heat 

 without expenditure of matter ? 



