60 NAVIN OX THE HOESE. 



"VII. The action of combustion and decomposition is the 

 more potent, the more the acts of respiration and circuLation 

 are accelerated, and the contact of the air with the blood be- 

 comes, in consequence, the oftener repeated. 



"Work can not be performed without the acts of respiration 

 and the pulsations of the heart becoming more energetic, and 

 proportionally so with the speed and intensity of the work; 

 the consequence of which is to bring the organic fiber often 

 into the presence of oxygen, and so to hasten combustion and 

 decomposition. 



"Chemical analysis shows that the products of combustion, 

 exhaled through the skin and lungs after a rapid course, are 

 considerably augmented; consequently, decom]30sition becomes 

 augmented under such circumstances. I pass over, in this 

 estimate of the causes of wear and tear in the animal ma- 

 chine, the nervous exhaustion consequent on muscular contrac- 

 tion, because, although I attach great importance to them, in 

 this discussion they are not necessary for my demonstration. 

 "VIII. The organism is opposed to this oxydation: 

 "1. By virtue of the innate force of cohesion existing be- 

 tween its component particles — a force which, for a certain 

 time, is able to counteract the affinity resulting from the action 

 of oxygen. 



"2. And especially through the continually rencAved influ- 

 ence of the aliments, introduced in sufficient quantity into 

 the digestive apparatus for furnishing the living tissue with 

 the elements proper for its reparation, and the oxygen of the 

 air with combustible matters, fit for the development and com- 

 pletion of its affinities, and, through combination with it, for 

 the production of the required animal heat. 



"IX. But if, while we are exacting continually from the 

 animal machine a large demand of strength — which, as I said 

 before, entails the introduction of a considerable quantity of 

 atmospheric air into the air passages— we do not affbrd a suf- 

 ficient supply of alimentary substance — that is to say, of 



