C 247 ] 



The ammonia given off from animal compounds 

 in putrefaction may be conceived to be formed at the 

 time of their decomposition by the combination of hy- 

 drogene and azote ; except this matter, the other pro- 

 ducts of putrefaction are analogous to those afforded 

 by the fermentation of vegetable substances ; and the 

 soluble substances formed abound in the elements, 

 which are the constituent parts of vegetables, in car- 

 bon, hydrogene, and oxygene. 



Whenever manures consist principally of matter 

 soluble in water, it is evident that their fermentation 

 or putrefaction should be prevented as much as pos- 

 sible ; and the only cases in which these processes can 

 be useful, are when the manure consists principally 

 of vegetable or animal fibre. The circumstances ne- 

 cessary for the putrefaction of animal substances are 

 similar to those required for the fermentation of vege- 

 table substances ; a temperature above the freezing 

 point, the presence of water, and the presence of oxy- 

 gene, at least in the first stage of the process. 



To prevent manures from decomposing, they 

 should be preserved dry, defended from the contact 

 of air, and kept as cool as possible. 



Salt and alcohol appear to owe their powers of 

 preserving animal and vegetable substances to their at- 

 traction for water, by which they prevent its decom- 

 posing action, and likewise to their excluding air. The 

 use of ice in preserving animal substances is owing to 

 its keeping their temperature low. The efficacy of 

 M. Appert's method of preserving animal and vegeta- 

 ble substances, an account of which has been lately 



