54 
MANURES. 
The great difference between the decay oi animal 
and vegetable matters is this, that as the animal 
bodies are far richer in the substance which forms 
ammonia, so they afford a richer source of manure. 
The. animal body contains that element in quantity 
enough, not only to fill the pores of its own mould, 
but also enough to impregnate a large quantity of 
mould from other sources. The vegetable body, on 
the contrary, contains scarcely enough ammonia to fill 
its own mould. Vegetables differ in the quantities of 
the elements of food which can furnish flesh and bood; 
and hence those vegetables are best for manure which 
furnish most- ammonia. We have already remarked 
on the difference, in this respect, between straws, 
grasses, and clover. But without going further into 
this comparison, which can have no other practical 
bearing than to show you the immense difference in 
value, in animal and vegetable bodies, in forming ma¬ 
nure, we may here resolve the subject into one great 
principle. The substance which forms flesh and blood, 
whether derived from plants or animals, alone forms 
ammonia during their decay, and the mould thence 
arising is rich or poor manure, just in proportion as it 
contains the substance fit to form flesh and blood. 
Starting from this principle, we find that animal sub¬ 
stances, as flesh, fish, fowl, the body generally, includ¬ 
ing its various forms of covering, hair, wool, feathers, 
nails, hoofs, horns, claws, &c., afford, in the process of 
decay, about ten times more ammonia than the straws 
and grasses usually entering into the compost heap. 
The animal bodies give more volatile alkali than their 
mould can contain. 
It is given off in such quantity that decay is rapidly 
hastened. All the signs of putrefaction, therefore, 
rapidly take place. The quantity of mould being 
small, nothing holds the volatile parts;, they escape 
anTl are lost. Now common sense and practical fore¬ 
sight have stepped in here, from time immemorial, and 
taught mankind the necessity and the utility of pre- 
