BONE DISORDER IN COWS. 
64-6 
cannot live upon white bread, sugar, or starch, if these are 
given as food, to the exclusion of all other substances. Nei¬ 
ther can a horse or cow live on hay alone: either will, sooner 
or later, give evidences of disease. They require stimulants. 
Common salt is a good stimulant. This explains why salt 
hay should be occasionally fed to milch cows; it not only 
acts as a stimulant, but is also an antiseptic, preventing 
putrefaction, &c. 
A knowledge of the constituents of milk may aid the 
farmer in selecting the substances proper for the nourishment 
of animals, and promotive of the lacteal secretion ; for much 
of the food contains those materials united, though not always 
in the same form. “The constituents of milk are cheese, or 
caseine—a compound containing nitrogen in large proportion; 
butter, in which hydrogen abounds; and sugar of milk, a 
substance with a large quantity of hydrogen and oxygen in 
the same proportions as in water. It also contains, in so¬ 
lution, lactate of soda, phosphate of lime, (the latter in very 
small quantities,) and common salt; and a peculiar aromatic 
product exists in the butter, called butyric acid.”— Liebig . 
It is very difficult to explain the changes which the food 
undergoes in the animal laboratory, (the stomach,) because 
that organ is under the dominion of the vital force—an im¬ 
material agency which the chemist cannot control. Yet we 
are justified in furnishing the animal with the elements of its 
own organisation; for, although they may not be deposited 
in the different structures in their original atoms, they may 
be changed into other compounds, somewhat similar. Liebig 
tells us that, whether the elements of non-azotised food take 
an immediate share in the act of transformation of tissues, or 
whether their share in that process be an indirect one, is a 
question probably capable of being resolved by careful and 
cautious experiment and observation. It is possible.that these 
constituents of food, after undergoing some change, are carried 
from the intestinal canal directly to the liver, and that there 
they are converted into bile, where they meet with the pro¬ 
ducts of the metamorphosed tissues, and subsequently com¬ 
plete their course through the circulation. 
This opinion appears more probable, when we reflect that 
as yet no trace of starch or sugar has been detected in arte¬ 
rial blood, not even in animals that have been fed exclusively 
with these substances. 
The following tables, from Liebig’s Chemistry, will give the 
reader the difference between what is taken into the system, 
and what passes out. 
