/. //■£, 



'^s of i 



THE BEGINNINGS OF II FE. 



25 



iispl 

 of 



Its 





^%, 



actt 



'at 



\ 



'^^ of force . 



\ (2) they^, 



■^■^^^in tissues. 

 ^omcna. 



y maintain I 

 of the medii 



« The alimentary substances introduced into the stomach, 

 after being digested and liquified, are absorbed and sent 

 into the vessels^ where they mix with the blood ; on the 

 other hand, the air introduced at each inspiration into 

 the pulmonary cavity yields to the blood a part of its 

 oxygen. Struck with this double centripetal move- 

 ment, Lavoisier asked himself what happened to these 



substances 



brought 



into relation with one another 



es 



Lis 



pecially tk 



amongst i: 



within the blood-vessels. Proceeding in this research 

 with all the rigour of a chemical analysis, he showed 

 that the oxygen introduced by the respiratory passages 



?ry great diffai attacks the organic substances furnished by digestion. 



.nd that of 



burns them 



combining with their carbon and their 



mpcrature beli hydrogen to form carbonic acid and water. He showed 



variously expli that this slow combustion of the organic materials of 



by Galen tliat^ the blood is an incessant source of heat 1.' Lavoisier 



left ventrit! then instituted experiments to determine the quantity 



lought tliat 



of heat abstracted from the animal by radiation, by 



ipon a spe 



lot only to 



and that' 



re 



striven 



nervous sy 



The tni« 

 id to 



at. 



be sa 

 nth ce 



ntury 



isco 



verier 



jjli contact with air, and by evaporation of fluids from the 

 surface of the body. On the other hand, he measured 

 the quantity of oxygen consumed, calculated the propor- 

 tions 6f carbonic acid and of water produced by the 

 combination of this oxygen with the materials of the 

 blood, and then estimated the quantity of heat dis- 

 engaged during these reactions. From a comparison 

 of the results thus obtained in these two series of ob- 

 servations, he came to the conclusion that the chemical 



r 



reactions carried on within the body would furnish 



to 

 steii 



i 







fl^ 



Gavar 



ret 



?a' 



1 ( 



M^m. de TAcad. des Sciences,' 1789 



