M. Dumas on the Chemical Statics of Organized Beings. 343 



it wns useful, as regarded your future studies, to give you in 

 writing and in a clearer form the expression of these views, 

 which were partly brought into existence under the stimulus 

 of your presence, and consequently reduced into form with 

 the hesitation which so often accompanies the first enuncia- 

 tion of our thoughts. 



II. — Since [the causes of] all the phaenomenaof life are ex- 

 erted upon matters which have for their base carbon, hydrogen, 

 azote, oxygen ; since these matters pass over from the animal 

 kingdom to the vegetable kingdom by intermediary forms, car- 

 bonic acid, water, and the oxide of ammonium ; lastly, since 

 air is the source whence the vegetable kingdom is fed, and 

 the reservoir in which the animal kingdom is annihilated ; we 

 are led to take a rapid survey of these different bodies with a 

 special view to general physiology. 



Composition of Water. — Water is incessantly formed and 

 decomposed in animals and plants ; to appreciate what results 

 from this, let us first see how it is composed. Some experi- 

 ments founded on the direct combustion of hydrogen, and in 

 which I have produced more than two pounds of artificial 

 water, — experiments which are in truth very difficult and very 

 delicate, but in which any errors would be unimportant with 

 regard to the circumstances which we are engaged upon, — 

 make it very probable that water is formed, in weight, 

 Of 1 part hydrogen 

 And 8 parts oxygen, 

 and that these whole and simple numbers express the true re- 

 lation according to which these two elements combine to form 

 water. 



As substances always present themselves to the eyes of the 

 chemist by molecules, as he always endeavours to connect in 

 his thoughfe, with the name of each substance, the weight of 

 the molecule, the simplicity of this relation is not unimport- 

 ant. 



In fact, each molecule of water being formed of one mole- 

 cule of hydrogen and one molecule of oxygen, we arrive at 

 these simple numbers, which cannot be forgotten. 



A molecule of hydrogen weighs 1 ; a molecule of oxygen 

 weighs 8 ; and a molecule of water weighs 9. 



Composition of Carbonic Acid. — Carbonic acid keeps inces- 

 santly forming in animals, and is continually undergoing de- 

 composition in plants ; its composition, therefore, deserves a 

 special notice in its turn. 



Now carbonic acid, like water, is represented by the most 

 simple numbers. 



Experiments founded on the direct combustion of the dia- 



