MANURES. 29 



failing of geine, the fruit fails, the plants die. Earths, and soils, 

 and geine, constitute, then, all that is essential and soils will 

 be fertile, in proportion as the last is mixed with the first. 

 The earths are plates, the salts the seasoning, the geine the 

 food of plants. The salts can be varied but very little in their 

 proportions without injury. The earths admit of wide variety 

 in their nature and proportions.* The doctrines of BERZE- 

 Liusand others, have encountered an opponent no less zealous 

 than intelligent in M. F. V. RASPAIL, a celebrated French 

 chemist, who, in his System of Organic Chemistry, now trans- 

 lated into English, denies the existence of any such proximate 

 principle in soils as geine. 



Of the means which nature employs for this purpose, fer- 

 mentation appears to be the chief. The elementary parts of 

 the substances fermented, assume new forms of combination, 

 and become fitted to supply the matter of nutrition to plants 

 in that form in which it can be received by the pores of the 

 roots. The process of fermentation is completed after the sub- 

 stance to be used as a manure is mixed with the matter of the 

 soil. It is common also to cause it to undergo a certain degree 

 of fermentation before it is mixed with the earth. This is the 

 method of preparing this class of manures for use, which is 

 employed in the practice of the farm. 



Animal matters decompose with facility when acted upon 

 by moisture and the air, the greater proportion of their ele- 

 mentary parts making their escape in various forms of gaseous 

 combination, leaving the earths, alkalies, and part of the car- 

 bonaceous matter remaining. But when this decomposition 

 takes place beneath the surface of the ground, these gaseous 

 compounds, as well as the carbon, which, when it combines 

 with oxygen, assumes also the gaseous state, is partially or 

 wholly retained in the earth, to afford the matter of nutrition 

 to the plants. 



Therefore no putrefactive process ought to be suffered to 

 proceed on a farmer's premises, without his adopting some 

 mode to save, as far as possible, the gaseous products of such 

 putrescence. These gaseous products, as has been observed, 

 constitute important elements of vegetable food, and a farmer 

 may as well suffer his cattle to stray away from his stall, or his 

 swine from their sty, without a possibility of reclaiming them, 

 as permit the principles of fertility expelled by fermentation 

 or putrefaction to escape into the atmosphere for the purpose 

 of poisoning the air, instead of feeding the plants. 



It is very easy to arrest these particles, and thereby prevent 



* Dr. DANA'S Letter to PROFESSOR HITCHCOCK. 

 3* 



