the most part retained in the body of the animal ; and the 
bitter principle, extract, saline matter, and tannin, when 
any exist, probably for the most part are voided in the 
excrement with the woody fibre. The extractive matter 
obtained by boiling the fresh dung of cows, is extremely 
similar in chemical characters to that existing in the soluble 
products from the grasses. And some extract, obtained 
by Mr. Sinclair, from the dung of sheep and of deer, which 
had been feeding upon the Lolium perenne, Dactylis glo- 
merata, and Trifolium repens, had qualities so analogous 
to those of the extractive matters obtained from the leaves 
of the grasses, that they might be mistaken for each other. 
The extract of the dung, after being kept for some weeks, 
had still the odour of hay. Suspecting that some undi- 
gested grass might have remained in the dung, which might 
have furnished mucilage and sugar, as well as bitter extract, 
I examined the soluble matter very carefully for these sub- 
stances. It did not yield an atom of sugar, and scarcely a 
sensible quantity of mucilage. 
Mr. Sinclair, in comparing the quantities of soluble 
matter afforded by the mixed leaves of the Lolium perenne, 
Dactylis glomerata, and Trifolium repens, and that obtained 
from the dung of cattle fed upon them, found their relative 
proportions as 50 to 13. 
It appears probable from these facts, that the bitter ex- 
tract, though soluble in a large quantity of water, is very 
little nutritive ; but probably it serves the purpose of pre- 
venting, to a certain extent, the fermentation of the other 
vegetable matters, or in modifying or assisting the function 
of digestion, and may thus be of considerable use in forming 
a constituent part of the food of cattle. A small quantity 
of bitter extract and saline matter is probably all that is 
needed, and beyond this quantity the soluble matters must 
be more nutritive in proportion as they contain more albu- 
men, sugar, and mucilage, and less nutritive in proportion 
as they contain other substances. 
In comparing the composition of the soluble products 
afforded by different crops from the same grass, I found, 
in all the trials I made, the largest quantity of truly nutri- 
tive matter, in the crop cut when the seed was ripe, and 
least bitter extract and saline matter; most extract and 
saline matter in the autumnal crop ; and most saccharine 
