The Chemical Statics of Organised Beings. 65 



You have seen, while discussing the experiments of MM. 

 Dulong and Despretz, you have positively seen the contrary 

 result from them. These skilful physicists supposed that an 

 animal placed in a cold water calorimeter comes out of it with 

 the same temperature that it had on entering it ; a thing abso- 

 lutely impossible, as is now well known. It is this cooling of 

 the animal, of which they took no account, that expresses in 

 their tableaux the excess of heat attributed by them and by all 

 physiologists to a calorific power peculiar to the animal and in- 

 dependent of respiration. 



It is evident to me that all animal heat arises from respira- 

 tion ; that it is measured by the carbon and hydrogen burnt, 

 In a word, it is evident to me that the poetical comparison of a 

 railroad locomotive to an animal is founded on a more serious 

 basis than has, perhaps, been supposed. In each there are 

 combustion, heat, motion ; three phenomena connected and pro- 

 portional. 



You see that, thus considering it, the animal machine be- 

 comes much easier to understand ; it is the intermediary 

 between the vegetable kingdom and the air ; it borrows all its 

 aliments from the one, in order to give all its excretions to the 

 other. 



Shall I remind you how we viewed respiration, a phenomenon 

 more complex than Laplace and Lavoisier had thought, or even 

 Lagrange had supposed, but which, precisely as it becomes 

 complicated, tends more and more to enter into the general laws 

 of inanimate nature ? 



You have seen that the venous blood dissolves oxygen and 

 disengages carbonic acid ; that it becomes arterial without pro- 

 ducing a trace of heat. It is not, then, in becoming arterial, that 

 the blood produces heat. 



But under the influence of the oxygen absorbed, the soluble 

 matters of the blood change into lactic acid, as MM. Mitscher- 

 lich, Boutron-Charlard, and Fremy observed; the lactic acid is 

 itself converted into lactate of soda ; this latter, by a real com- 

 bustion, into carbonate of soda, which a fresh portion of lactic 

 acid decomposes in its turn. This slow and continued succession 

 of phenomena which constitutes a real combustion, but decom- 

 posed at several times, in which we see one of the slow combus- 

 tions to which M. Chevreul drew attention long ago, this is the 

 true phenomenon of respiration. The blood then becomes oxy- 

 genised in the lungs ; it really breathes in the capillaries of all 

 the other organs, there where the combustion of carbon and the 

 production of heat principally take place. 



A last reflection. To ascend to the summit of Mont Blanc, a 

 man takes two days of twelve hours. During this time he burns 

 at an average 300 grammes of carbon, or the equivalent of 

 3d Ser. — 1842. IT. f 



