ORGANIC CHEMISTRY. 7 



kingdom. The catalogue of elementary, or 

 simple bodies, existing in nature, is, indeed, 

 more extensive than the list of those which 

 enter into the composition of animal or vege- 

 table substances. But in the mineral world 

 they occur in simpler combinations, resolvable, 

 for the most part, into a few definite ingredients, 

 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 diver- 

 sity. Simple binary compounds are rarely ever 

 met with ; but, in place of these, we find three, 

 four, five, or even a greater number of consti- 

 tuent 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 nume- 

 rous, require to be much more nicely balanced, 

 in order to retain them in combination. Slight 

 causes are sufficient to disturb, or even overset, 

 this equipoise of affinities, and often produce 

 rapid changes of form, or even complete decom- 

 position. The principles, thus retained in a 

 kind of forced union, have a constant tendency 



