VITAL AFFINITY. 7 



All living- beings, whether animals or plants, are composed, 

 essentially, of four chemical elements, Carbon, Hydrogen, Oxy- 

 gen, and Nitrogen, which are combined in various proportions. 



It would be very natural to suppose after this statement that 

 these chemical combinations are such as you see exhibited every 

 day around you; such as are called the natural chemical affin- 

 ities, which exist, for instance, between the gases of which the 

 air is composed, or the acids, chloroforms, alcohol, salts, crystals, 

 &c., &c. But this is not so ! Although I am well aware that 

 it is getting to be the general opinion, among organic chemists 

 and physiologists, that the inorganic and organic affinities ap- 

 proximate each other, and may eventually turn out to be, among 

 themselves, mere degrees of difference ; yet, even with such an 

 idea in view, it is not incorrect to say that it is in direct opposi- 

 tion to natural chemical affinity that organized beings exist. 



There is another principle or affinity which is not commonly 

 recognized in our daily experience ; it is the principle of life, or 

 vital affinity, which binds together the chemical elements in 

 certain forms or groups, which are nowhere known but in or- 

 ganized, living beings. Between these two kinds of affinities, 

 then, the natural chemical affinity on the one hand, and the 

 vital affinity on the other, there is a constant struggle, the one 

 to counteract the operations of the other. 



Perhaps this question may arise in your minds, as it has with 

 me, namely, Why should inorganic chemical affinities be called 

 the natural affinities, any more than those which are exhibited 

 by organic life ? Is not one as extensive in its influence as the 

 other, and does not the vital affinity, in assimilating material 

 for organized bodies, tend just as much to decompose bodies 

 held together by the natural chemical affinities, as in the reverse 

 way ? I cannot anticipate what may be thought of this ques- 

 tion by the physical causists, those who maintain that life, 

 organized bodies, originate through the operations of physical 

 agencies, or in other words, the natural chemical affinities. Can 

 the latter transform themselves into vital affinities ? It may be 

 so, if the two differ from each other only in degree. 



