EXAMPLES. 291 



bines with the muriatic acid. Here the contact of 

 muriatic acid with water and hydrocyanic acid caus- 

 es a disturbance in the attraction of the elements of 

 both compounds, in consequence of which they ar- 

 range themselves into new combinations, one of 

 which, — ammonia, — possesses the power of uniting 

 with the acting body. 



Inorganic chemistry can present instances analo- 

 gous to this iclass of decomposition also ; but there 

 are forms of organic chemical decomposition of a 

 very different kind, in which none of the component 

 parts of the matter which suffers decomposition enter 

 into combination with the body which determines the 

 decomposition. In cases of this kind a disturbance 

 is produced in the mutual attraction of the elements 

 of a compound, and they in consequence arrange 

 themselves into one or several new combinations, 

 which are incapable of suffering further change under 

 the same conditions. 



When, by means of the chemical affinity of a sec- 

 ond body, by the influence of heat, or through any 

 other causes, the composition of an organic compound 

 is made to undergo such a change, that its elements 

 form two or more new compounds, this manner of 

 decomposition is called a chemical transformation or 

 metamorphosis, ' It is an essential character of chem- 

 ical transformations, that none of the elements of the 

 body decomposed are singly set at liberty. 



The changes, which are designated by the terms 

 fermentation, decay, and putrefaction, are chemical 

 transformations effected by an agency which has 

 hitherto escaped attention, but the existence of 

 which will be proved in the following pages. 



