114 



CHANGES IN FARM-YARD MANURE 



Fermentation of Farm-yard Manure. Fresh manure soon be- 

 gins to ferment and to change its character. This is due to the effect 

 of the micro-organisms which find a suitable breeding ground in the 

 complex organic substances present in the manure. An account of 

 the bacteria of stable manure and their action was given in a paper by 

 Herzfeld. 1 



According to this paper,, the fermentations which manure undergoes, 

 partly in the stables etc., but mainly in the heap and finally on the 

 land, may be divided into 



(a) Fermentations of the fatty acids. 



(b) Fermentations of the amino-compounds. 



(c) Putrefactive fermentation. 



(d) Ammoniacal or urea fermentation. 



(e) Sulphuretted hydrogen fermentation. 

 (f) Cellulose or methane fermentation. 



(g) Fermentations of the carbohydrates. 



(a) Many of the fatty acids, or rather their salts (best the calcium 

 salts), are capable of undergoing changes under the action of various 

 bacilli, micrococci and other bacteria, generally giving rise to the for- 

 mation of other simpler organic acids, often carbon dioxide and, some- 

 times, hydrogen and alcohol. 



(b) Amino-acids and other amino-compounds, i.e., compounds con- 

 taining (NH 2 ), are formed by the putrefaction of albumin. Tyrosine, 

 OH.C G H 4 .CH 2 .CH(NH 2 ).COOH, para-hydroxyphenyl a-amino-pro- 

 pionic acid, leucine, CH 3 .(CH 2 ) 3 .CH(NH 2 ).COOH, a-amino-caproic 

 acid, asparagine, COOH.CH 2 .CH(NH 2 ).CONH 2 , amino-succinamic 

 acid, and glycocoll, CH 2 .(NH 2 ).COOH, amino-acetic acid, are among 

 such products. 



Tyrosine is converted by fermentation, if air be excluded, into 



indol, CffLS ^^H, carbon dioxide, and hydrogen; in the pre- 



\CH^ 

 sence of air, other substances, like phenol, C t; H 5 OH, are formed and the 



1 Zentralblatt fur Bacteriologie, 1895, and Jour. Soc. Chem. Ind., 1895, 449. 



