NATURE OF FERMENTATION. 31 



the presence of certain food constituents, especially 

 nitrogenous bodies, were necessary. 



Subsequent researches by Pasteur and others have 

 conclusively demonstrated that the micro -organic life, 

 instrumental in effecting the putrefaction or decay 

 of organic matter of any kind, may be divided into two 

 great classes : 



1. Those which require a plentiful supply of oxygen 

 for their development, and which, when bereft of 

 oxygen, die known as aerolies. 



2. Those which, on the contrary, develop in the 



'Book of the Farm,' Division III. p. 98, a farm-horse makes about 

 12 tons of manure in a year. 1 



It has been calculated that cows void about 48 per cent of the dry 

 matter of their food in the solid and liquid excreta, which contains of 

 water, on an average, 87.5 per cent. That is, every pound of dry matter 

 will furnish 3. 84 Ib. of total excreta. By adding the necessary amount 

 of straw for litter (which may be taken at one-third the weight of the 

 dry matter of the fodder), Heiden calculates that an ox weighing 1000 

 Ib. should produce 113 Ib. of manure in a day, or 20 tons in a year. 

 The ' Book of the Farm,' Division III. p. 98, gives the annual amount 

 at from 10 to 14 tons. According to Wolff, one may assume that on 

 an average the fresh excrements (both liquid and solid) of the 

 common farm animals (with the exception of the pig) contain of 

 every 100 Ib. of dry matter in the food consumed about 50 Ib., or a 

 half. Estimating the dry matter in the litter used at equal to about 

 of the dry matter of the food, this would mean that for every 

 100 Ib. of dry matter consumed in food there would be 75 Ib. of 

 dry manure (viz., 50 Ib. dry excrements + 25 Ib. dry litter), which 

 would yield 300 Ib. of farmyard manure in the wet state i.e., with 

 75 per cent water. The amount of food daily required per every 

 1000 Ib. of live weight of the common farm animals may be taken, 

 roughly speaking, at 24 Ib. dry food material and 6 Ib. of straw as 

 litter. The daily production of manure for 1000 Ib. of live weight 

 would amount, therefore, to 18 Ib. of dry, or 72 Ib. wet manure. 



