312 DR ALISONS OBSERVATIONS ON 



formed by the union of azote fi-om the atmosphere with hydrogen from water, 

 whenever another substance, exerting an attraction for the oxygen of the water, 

 is present. — {Chemistry of Vegetable and Animal Physiology, p. 149, et seq.) 

 Now, as carl)onic acid and water form starch, or its allied compounds, in the 

 living vegetable, by the attraction of carbon for the elements of water, to the ex- 

 clusion of oxygen ; and as the starch then forms oil, by the attraction of the 

 carbon to hj'drogen, to the exclusion of great pai-t of the remaining oxygen ; 

 so, on the introduction of ammonia, or its elements in a state fit for entering into 

 new combinations, into the scene of those metamorphoses, it is only in accordance 

 with what we know of the nature of these vital affinities, to suppose that the car- 

 bon may attach to itself the elements of this ammonia, to the exclusion of the 

 elements of water and of oxygen, matters which are known to be continually 

 thrown off by vegetables, during the continuance of these vital processes. Thus 

 we have the elements of starch, 48 C, 40 H, 40 plus the elements of ammonia, 

 (5 N, 18 H, = 48 C, G N, 58 H, 40 = 48 C, 6 N, 36 H, 14 (the elements of albu- 

 men) jo/f/s 22 H + 40, a considerable quantity of the water, and a small quan- 

 tity of the oxygen, which are continually exhaled by the plant. 



Thus, during the whole process of the formation of organic compounds in the 

 vegetable, we see that the vital affinities shew themselves by the attractions of 

 Carbon, first for the elements of water in preference to oxygen, then, either for the 

 hydrogen of those elements, in preference to the oxygen, or for the elements of 

 water, with an excess of hydrogen, along with those of ammonia ; and thus, by 

 tliese peculiarities of attraction of Carbon, for the elements of water, for hydrogen, 

 and for azote, — to the more or less complete exclusion of oxygen, — we see that the 

 essential materials of all organized matters may be easily formed, ■ while water 

 and oxygen, the known excretions of vegetables, only escape. 



The point at this moment most disputed, and the settlement of which is most 

 essential to the precise comprehension of the nature of vital affinities, is. Whether 

 there is any formation of albuminous matter in animal bodies ? and it is obvious, 

 that there is a difficulty in regard to its formation from starch, just similar to 

 that which was stated as to the formation of oil in the animal body, because 

 we see no evolution of oxygen ; but it is also certain that this may be got over, 

 precisely in like manner as in the former case, by supposing — what is quite 

 in accordance with known facts — that a considerable absorption of the oxygen of 

 the air attends the process, and that, Avith its help, a large portion of the carbon 



* This may be shortly stated thus CO.. + HO = Carbonic acid and water. From this is formed, 



C + H + = Sugar, oxygen going off. From this, 

 C_j^ H'g 0,„ = Starch, water going off. From this, either 



C,^ H^„ O4 = Fat, oxygen going off. Or, 



C4, Nj^ Hj"' Ojj = Albumen, ammonia being added, and water and 

 a little oxygen going off. 



