CONTENTS OF THE MANURE HEAP 77 
which represents the result of the nitrogenous metabolism of 
animal life. This liquid manure is by far the most valuable part 
of the manure, since it contains the nitrogen which has been actu- 
ally metabolized by animals, and which can now be brought back 
readily into a condition available for plant life. The liquid 
manure contains three-fourths of the total nitrogen of the whole 
heap, and four-fifths of the total potash. But farmers some- 
times fail to realize this, and allow this material to waste by soak- 
ing into the ground. In addition to these ingredients manure 
always contains a large amount of water and an unknown number 
of species and varieties of bacteria in very great abundance. 
In this manure the bacteria find plenty of food and moisture 
and their growth is rapid. There is a great struggle for existence 
among them and, in the weeks of fermentation, first one and then 
another species may gain mastery. If the bacterial contents of 
such a mass be studied at intervals, the number and variety of 
species which are most abundant are found to be constantly 
changing. 
Losses from the Manure Pile.—The result of this bacterial 
growth is an extensive and profound series of chemical changes 
by which the manure is profoundly modified. These are partly 
useful and partly injurious, but, taken as a whole, they are neces- 
sary. Most of the material in the manure is in a form not capable 
of being used by plants, and must be greatly transformed before it 
isavailable for vegetation. Thetransformations are much thesame 
as those we have already considered in the soil, but they take place 
under different conditions, which somewhat modify thém. In our 
study of the subject it should be borne in mind that the most im- 
portant feature of manuring is the furnishing of nitrogen to the 
crops, and the first care should be to protect this material and 
avoid its loss. 
The losses from manure are due to two causes. (1) Leaching. 
A considerable portion of the nitrogen is in a soluble form, includ- 
ing all of that in the liquid manure. From manure heaped upon 
