CAUSES OF PUTREFACTION. 127 



the meat does not decompose ; and though the heat would rarify 

 the air and leave but a small trace behind, still the experiment 

 can be repeated so as to leave a certain amount of atmosphere 

 purified by tlie prolonged action of heat, and the meat keeps. 



You will thus appreciate that we have to search for other 

 agencies as to the causes of putrefaction besides those which 

 chemists have been pleased to define. Liebig once said : " In 

 the formation of animal and vegetable substances, the vital prin- 

 ciple opposes, as a force of resistance, the action of the other 

 forces, cohesive attraction, heat and electricity — forces which 

 render the aggregation of atoms and combinations of the high- 

 est order impossible except as living organisms. Hence it is," 

 he continues, " that when those complex combinations which 

 constitute organic substances are withdrawn from the influence 

 of the vital force — when this no longer is opposed to the action 

 of the other disturbing forces, great alterations immediately 

 ensue in their properties and in the arrangement of their con- 

 stituents. The slightest chemical action, the tnere contact of 

 atmospheric air, suffices to cause a transposition of their atoms, 

 and to produce new arrangements ; in one word, to excite 

 decomposition. Those remarkable phenomena take place which 

 are designated by the terms fermentation, putrefaction and 

 decay ; these are the processes of decomposition, and their ulti- 

 mate results are to reconvert the elements of organic bodies into 

 that state in which they exist before they participate in the proc- 

 esses of life." The vital principle which was said by Liebig to 

 oppose the continual action of the atmosphere, moisture and 

 temperature upon the organism, has been termed vis vita, 

 whereas vis inertia implies the property whereby the elements 

 of dead organic matter retain passively the position and condition 

 in which they have been placed. 



The great tendency manifested by organic and especially 

 animal compounds to decomposition has been in times past 

 ascribed to the large amount of nitrogen they contain. This 

 gas is supposed by some to be simply mixed with oxygen in 

 forming the air, from the readiness with which the latter is 

 appropriated by animals and even inert matter. It is not parted 

 with by animal tissues so long as they retain their structure and 

 life. But death and nitrogen gas, according to some old author- 

 ities, might be defined by the same sentence — " principle of dis- 



