84 ASSIMILATION OF HYDROGEN. 



water, form 1 eq. of Amylin, or starch, with separa- 

 tion of 6 eq. carbonic acid. 



We can explain, in a similar manner, the forma- 

 tion of all the component substances of plants 

 which contain no nitrogen, whether they are pro- 

 duced from carbonic acid and water, with separation 

 of oxygen, or by the conversion of one substance 

 into the other, by the assimilation of oxygen and 

 separation of carbonic acid. We do not know in 

 what form the production of these constituents takes 

 place; in this respect, the representation of their 

 formation which we have given must not be received 

 in an absolute sense, it being intended only to ren- 

 der the nature of the process more capable of ap- 

 prehension; but it must not be forgotten, that if the 

 conversion of tartaric acid into sugar, in grapes, be 

 considered as a fact, it must take place under all 

 circumstances in the same proportions. 



The vital process in plants is, with reference to 

 the point we have been considering, the very re- 

 verse of the chemical processes engaged in the for- 

 mation of salts. Carbonic acid, zinc, and water, 

 when brought into contact, act upon one another, 

 and hydrogen is separated, while a white pulverulent 

 compound is formed, which contains carbonic acid, 

 zinc, and the oxygen of the water. A living plant 

 represents the zinc in this process : but the process 

 of assimilation gives rise to compounds, which con- 

 tain the elements of carbonic acid and the hydrogen 

 of water, whilst oxygen is separated. 



Decay has been described above as the great 

 operation of nature, by which that oxygen, which 

 was assimilated by plants during life, is again re- 

 turned to the atmosphere. During the progress of 

 growth, plants appropriate carbon in the form of 

 carbonic acid, and hydrogen from the decomposition 

 of water, the oxygen of which is set free, together 

 with a part of all of that contained in the carbonic 

 acid. In the process of putrefaction, a quantity of 

 water, exactly corresponding to that of the hydro- 



