CHAPTER VI. 
THE MANURE HEAP AND SEWAGE. 
CONTENTS OF THE MANURE HEAP. 
The value of the manure heap is recognized by every farmer. 
So thoroughly is this appreciated that, in some countries, the wealth 
of the farmer is measured by the size of his manure heap, which 
is commonly exposed prominently in front of his house. Every- 
where one may measure quite accurately the thrift of a farmer by 
an examination of this somewhat unsavory product of farm life, 
and the extent of his intelligence may likewise be gauged by the 
care he bestows upon it. We can readily understand its importance 
when we remember that in this manure heap are going on, in a 
condensed space, exactly the transformations of food material 
which we have been considering. 
The manure heap is always an extremely complex mixture 
of organic substances, of nearly every conceivable kind. It contains 
great quantities of partly broken-down vegetable tissues, which have 
passed through the alimentary canal of the cattle, partly digested. 
It will contain large or small amounts of hay or straw derived from 
bedding and from the incompletely digested food, especially if 
horses contribute to its formation. It may contain sawdust or 
some other form of woody tissue. It will be likely to contain more 
or less flesh and bone from dead animals, and will be sure to contain 
proteids, albuminoids, gelatins, fats, sugars, starches, and, indeed, 
nearly all types of organic matter produced by animals or plants, 
all of which will be in various stages of digestion and decomposition. 
Lastly, and perhaps most important, it will contain much nitrogen 
in the form of urea, in the liquid manure, 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 
