260 EREMACAUSIS OR DECAY. 



the same matter, at a very slightly elevated temper- 

 ature ; and putrefaction as a process of oxidation, 

 in which the oxygen of all the substances present 

 comes into play. 



EREMACAUSIS OR DECAY. v 



In organic nature, besides the processes of de- 

 composition named fermentation and putrefaction, 

 another and not less striking class of changes oc- 

 cur, which bodies suffer from the influence of the 

 air. This is the act of gradual combination of the 

 combustible elements of a body with the oxygen of 

 the air ; a slow combustion or oxidation, to which 

 we shall apply the term of eremacausis. 



The conversion of wood into humus, the forma- 

 tion of acetic acid out of alcohol, nitrification, and 

 numerous other processes, are of this nature. Vege- 

 table juices of every kind, parts of animal and vege- 

 table substances, moist sawdust, blood, &c., cannot 

 be exposed to the air, without suffering immediately 

 a progressive change of colour and properties, 

 during which oxygen is absorbed These changes 

 do not take place when water is excluded, or when 

 the substances are exposed to the temperature of 

 32, and it has been observed that different bodies 

 require different degrees of heat, in order to effect 

 the absorption of oxygen, and, consequently, their 

 eremacausis. The property of suffering this change 

 is possessed in the highest degree by substances 

 which contain nitrogen. 



