the Progress of English Agriculture. 839 = 573 
^ase ; the composition of the animals themselves and of their 
crease ; the relation of the constituents stored in the increase 
those consumed ; and, by difference, the proportion of the 
i)d constituents expired, perspired, or voided in the dung. 
Numerous analyses of the excrements of oxen, sheep, and 
i^s, fed on foods of known composition, have also been made 
Messrs. Lawes and Gilbert ; and from all the results of these 
portant inquiries, it has been estimated that in the valuation 
animal manure, founded on a knowledge of the composition 
the food, 90 per cent, of the nitrogen of the food may be Proportion of 
, -koned to be recovered in the manure in the case of cakes, °'ti"og«° *^he 
; Ise, and other highly nitrogenous feeding-stuffs ; and 85 per in°m;mure!"^'^ 
4Tit. in the case of foods comparatively poor in nitrogen, such 
s the cereal grains and roots ; and less than 65 per cent, in the 
<5e of bulky feeding-stuffs, such as hay and straw. 
The investigations have proved that our farm stock, even in 
h store condition, contain less nitrogenous substances and 
i)re fat than was previously supposed, and that the so-called 
i tening process, in fact, consists in the deposition of fat in the 
iimal body in a much greater degree, and that of lean muscle 
i a much less degree, than was formerly supposed. 
Another important general result of Messrs. Lawes and 
< Ibert's feeding experiments is that the amount of increase in 
le weight and in fat is, as our fattening foods go, much more 
(pendent upon the amount of non-nitrogenous than upon that 
< the nitrogenous constituents which the food supplies. 
In other words, the comj)arative values of our fattening foods, 
c. a source of saleable animal increase, depend more on their 
a ount of digestible and assimilable non-nitrogenous consti- 
tmts than on that of the nitrogenous ; but, as a source of 
i nure, their value is the greater the higher their proportion 
^nitrogenous compounds. 
(n the case of young stock or milking-cows not over well 
S)plied with concentrated purchased foods, the dung w^ill not 
1: quite so valuable as that of fattening-stock, inasmuch as a 
sail proportion of the nitrogenous and phosphatic food con- 
s uents will be stored up during the increase in the live weight 
o:he young animal, or will be expended in the production of 
nlk ; still, even in the case of growing store cattle or milking- 
cvs, by far the larger proportion of the nitrogen and the 
p)sphates of the food will be rejected in the solid and liquid 
« Tements. 
t is well to bear in mind that the estimated manure value of Estimated 
1 chased foods has nothing: to do with mere speculation, but '"^""'j'^ ^'^^^^ 
11 . 1 ^ 1 1 1- 1 1 of foods, 
fits upon well-ascertained tacts, brought to light by numerous 
1< Jing experiments in this and other countries. The rate of 
i 
