36 
MANURES. 
salts, have prepared the way for our entering upon 
the next section—the second class of manures. 
SECTION VIII. 
MANURES CONSISTING OF SALTS. 
In using the term salts here, to designate a class of 
manures, I wish to distinguish between these and 
mineral manures, as they are usually termed. These 
manures are similar in kind to the salts, whose action 
in cow dung we have already considered. They are 
truly mineral salts, derived from the mineral king¬ 
dom, entering into and forming a part of plants, and 
from this source introduced into the dung of animals. 
Their action, whatever be their name, has been ex¬ 
plained. But the salts composing the second class of 
manures now under consideration, are not of mineral 
origin. They are derived from the animal kingdom. 
The source from which they are formed is the living 
process of the animal body. They are animal salts. 
Here, then, let us divide the second class of manures 
into animal salts, which are truly manures, both their 
base and their acid acting as nourishers of plants, and 
into mineral salts. Here again, reader, you will find 
that the few facts which we have pointed out, re¬ 
lating to the food and nourishment of animals, will 
help us on our way, in tracing the source of these ani¬ 
mal salts. 
It has been already said, that the food of animals is 
divided into two classes: that which does, and that 
which does not contain nitrogen. All domestic ani¬ 
mals eat these classes together. In a lew words, let 
us trace their course after the anim* 1 has digested 
