6 THE VITAL lUNtTlONS. 



kingdom, in like manner, furnishes Gelatin, Albu- 

 men, Fibrin, Mucus, Entomoline, Elearin, Stearin, 

 and many others. 



The chemical constitution of these organic pro- 

 ducts, formed, as they are, of but few primary 

 elements, is strikingly contrasted with that of the 

 bodies belonging to the mineral kingdom. The 

 catalogue of elementary, or simple bodies, exist- 

 ing in nature, is, indeed, more extensive than the 

 list of those which enter into the composition of 

 animal or vegetable substances. But in the mineral 

 world they occur in simpler combinations, resolv- 

 ible, for the most part, into a few definite ingre- 

 dients, which rarely comprise more than two or 

 three elements. In organized products, on the 

 other hand, although the total number of existing 

 elements may be smaller, yet the mode of com- 

 bination in each separate compound is infinitely 

 more complex, and presents incalculable diversity. 

 Simple binary compounds are rarely ever met 

 with ; but, in place of these, we find three, four, five, 

 or even a greater number of constituent elements 

 existing in very complicated states of union. 



This peculiar mode of combination gives rise 

 to a remarkable condition, which attaches to the 

 chemical properties of organic compounds. The 

 attractive forces, by which their several ingredients 

 are held together, being very numerous, require to be 

 much more nicely balanced, in order to retain them 

 in combination. Slight causes are sufl^icient to dis- 

 turb, or even overset, this equipoise of affinities, and 

 often produce rapid changes of form, or even com- 

 plete decomposition. The principles, thus retained 

 in a kind of forced union, have a constant tendency 



