THE MANURE HEAP AND SEWAGE. I I I 



abundant are found to be constantly changing. Different sam- 

 ples of manure from the same pile at the same time or at dif- 

 ferent times are almost sure to give different results to bacterio- 

 logical analyses. All of this indicates faintly the wonderful 

 complexity of bacterial life and the intensity of the struggle for 

 existence among the numerous species originally present in the 

 manure. Of all this, however, we have as yet only the faint- 

 est notion and must rest content with the knowledge that bac- 

 terial life is excessively active, and that now one, and now an- 

 other species, gains the upper hand and produces its effect 

 upon the decomposing organic materials. 



FERMENTATIONS IN MANURE. 



Destructive. The first chemical changes which go on are 

 those of decomposition. An ammomacal fermentation is univer- 

 sal, as indicated by the ammonia smell which always appears. 

 The liquid manure is most rapidly decomposed by this fermen- 

 tation, this substance in a very few days, and perhaps in only 

 a few hours, suffering the reduction into ammonia compounds 

 as already mentioned above. This is completed before the 

 ammoniacal fermentation of the other nitrogen bodies has 

 fairly begun, and indicates that the proper method of handling 

 manure will be to treat the liquid manure separately from the 

 solid portion. Eventually all of the proteid matter is likely to 

 undergo ammoniacal fermentation. But this is not all. The 

 starches, sugars, cellulose and woody tissue, in time, undergo 

 a decomposition by which CO 2 is set free and various other 

 substances are left. The fats and fatty acids are decomposed 

 with the formation of CO 2 and butyric acid, together with other 

 less known bodies. The decomposition of the proteids liber- 

 ates sulphur, commonly as H 2 S, and this unites with water to 

 form sulphuric acid. The sulphuric acid may combine with 

 the ammonia to form ammonia sulphates, or the ammonia may 

 unite with the carbon to form carbonates. A large quantity of 



