10 CHEMICAL COMPOSITION OF HUM AX BODY. 



equivalents of oxygen to two of hydrogen, is among the 

 substances most easily decomposed. 



The instability, on this ground, belonging to organic 

 compounds, is, in those which are most abundant in the 

 highly organized tissues of animals, augmented, 1st, by 

 their containing nitrogen, which, among all the elements, 

 may be called the least decided in its affinities, and that 

 which maintains with least tenacity its combinations with 

 other elements ; and, 2ndly, by the quantity of water 

 which, in their natural state, is combined with them, and 

 the presence of which furnishes a most favourable con- 

 dition for the decomposition of nitrogenous compounds. 

 Such, indeed, is the instability of animal compounds, 

 arising from these several peculiarities in their constitu- 

 tion, that, in dead and moist animal matter, no more is 

 requisite for the occurrence of decomposition than the 

 presence of atmospheric air and a moderate temperature ; 

 conditions 50 commonly present, that the decomposition of 

 dead animal bodies appears to be, and is generally called, 

 spontaneous. The modes of such decomposition vary ac- 

 cording to the nature of the original compound, the tem- 

 perature, the excess of oxygen, the presence of microscopic 

 organisms, and other circumstances, and constitute the 

 several processes of decay and putrefaction ; in the results 

 of which processes the only general rule seems to be, that 

 the several elements of the original compound finally unite 

 to form those substances, whose composition is, under the 

 circumstances, most stable. 



The organic compounds existing in the human body may 

 be arranged in two classes, namely, the azotized or nitro- 

 genous, and the non-azotized, or non-nitrogenous principles. 



The non- azotized principles include the several fatty, oily, 

 or oleaginous substances, as olein, stearin, cholesterin, and 

 others. In the same category of non-nitrogenous substances 

 may be included lactic and formic acids, animal glucose, 

 sugar of milk, &c. 



