of sulphate; also, how much phosphoric acidis worth ina solut 
or available form, since he has at command the very sega 
products. 
THE CoMMERCIAL VALUATION OF THE Foop ConsTITUENTS OF Foops. 
As we have seen, therefore, it is only necessary, in any given — 
sample of food, to determine by chemical analysis the amount of 
nitrogen, potash and phosphoric acid in such food, and then, by 
simple calculation, to estimate the value of these according to the — 
market rates, in order to determine the commercial value of the 
fertilizing constituents in such sample. a 
But in the determination of the food value, commercially, ofthe 
different food constituents of a sample of food, we have a far 
more difficult task, and can hope at best, with our present knowl- 
edge, to only approximate it. i: 
These food constituents are the albuminoids, the carbohydrates _ 
(starch and sugars), and the fats or oils; we may include also the 
erude fiber. 
All the ordinary forms of cattle foods contain each of the above _ 
constituents in very varying proportions, but in affixing a value to 
these we have not, as is the case with fertilizing constituents, any _ 
one food consisting wholly or mainly of one of these food con- | 
stituents, which we may use as a basis for valuation. It is true’ — | 
that sugar, starch, albumen and fat are found pure in the market, 
but these have been produced to meet other demands of the 
market, and the cost of their production is such as to render 
them valueless as means by which their value in any food con- _ 
taining them may be determined. 
The following table gives the percentage composition of twelve 
approximately, and the number of pounds of the several food a 
constituents Ve in 2,000 pounds of each of these foods which 
