It is pretty well known what the constituents of the animal organism
are, and what elements of nutrition are required in the food for the
sustenance of the animal. Of these primal elements--some twelve or
fifteen in number--it is found that, practically, when foods combined
contain two of them in proper proportion, the rest are generally
present in sufficient quantity. These two are CARBON and
NITROGEN, and the foods containing them in relatively large
proportion are respectively called _carbonaceous_ and _nitrogenous_.
All foods contain these elements in greater or less proportion. The
proper proportion for feeding is found to be about _one_ of nitrogen to
_five_ or _six_ of carbon. If the temperature of the weather is low,
the proportion of carbon may be raised to eight, and even ten, where
little exercise is had--as, for instance, milch cows standing in a cold
stable. But, in hot weather, when cows are giving milk, the carbon may
be reduced to four and even three--that is, so that there shall be
one part of nitrogen to three or four parts of carbon. The carbon is
heat and fat producing, and some class it as motor producing, but we
think this is a mistake, save so far as heat is essential to motion. We
think nitrogen is motor producing as well as muscle producing--or, in
other words, that the element which produces the organs of motion also
fills them with energy, for the exercise of which heat is essential. We
cannot have motion, or even life, much below the normal temperature of
about 98 degrees Fahrenheit. At all events, it is found necessary to
feed nitrogenous food to all animals that are working hard, to supply
the waste of muscle--and we think also to replace the expended energy.
Dr. J. Milner Fothergill, in his work on the "Maintenance of Health,"
published by G.P. Putnam's Sons, says: "The effect of the nitrogen
upon the brain is to _evolve nerve force freely_, and this rules and
regulates the actual force which takes its origin in the respiratory
foods consumed. These respiratory foods furnish the force itself, but
the nitrogenized foods furnish the manifesters of force." It appears to
us that the nerve force, which he says is evolved, is all there is of
it, save the requisite conditions afforded by heat. Dr. Houghton says:
"The hunted deer will outrun the leopard in a fair open chase, because
the force supplied to its muscles by vegetable food is capable of being
given out continuously for a long period of time; but in a sudden
rush at a near distance, the leopard will infallibly overtake the
deer, because its flesh food stores up in the blood a reserve of force
capable of being given out instantaneously in the form of exceedingly
swift muscular action." Dr. Fothergill goes on to say: "Nitrogen is
the essential factor in all explosive compounds, from gunpowder to
nerve force. It endows the consumer of it with energy and enables him
to discharge his force quickly and rapidly." Again, he says of the
race-horse: "His food affects his speed and endurance, and without his
nitrogenized food he would cut a poor figure at a race, because without
it he could not discharge his force fast enough."