BACTERIA IN FARMYARD MANURE 215 



reduced. Voelcker's analyses of a heap of farmyard 

 manure composed of a mixture of the excreta of horses, 

 cows, and pigs, with the usual straw litter, showed a loss 

 of 20 per cent, of its weight when the straw was half 

 rotted ; at a later stage, when the heap was " fatty " or 

 " cheesy " in texture, it was reduced 40 per cent, and 

 when the fermentations or decompositions were practically 

 complete the heap was found to have lost 50 to 60 per 

 cent, of its original weight. 



2, Bacteria in Farmyard Manure. Normal urine 

 when it is excreted is free from living organisms, but the 

 solid faeces of all kinds of animals contains vast numbers 

 of bacteria. Wuterich and Freudenreich examined the 

 fresh dung of two cows fed on grass, and found that in 

 one case the number present in a gram of dung was 

 10 and 12 J millions respectively on two separate days, 

 in the other the numbers were 1.8 and 4 millions on the 

 same days. Later, after feeding the same animals with 

 hay the number of the bacteria in the dung rose in the 

 case of one cow to 187 millions, and in the other to 

 387 millions per gram. The numbers found by Savage 

 in the dung of three horses examined was from ij to 

 2 millions, in four cows from I to 10 millions, and in 

 three pigs examined the solid excreta contained 10 

 to 100 millions per gram. The most characteristic 

 bacterium present in especially large numbers in the 

 intestines and in the fresh faeces of all kinds of animals 

 is Bact. coli, of which there are several very slightly 

 modified forms differing in their power of fermenting 

 carbohydrates. Wuterich and Freudenreich found Bact. 

 colt chiefly in the faeces of cows along with a smaller 

 number of Bs. subtilis and Bact. Schafferi. Savage found 

 many streptococci as well as Bact. coli in the faeces of 



