The question of alimentation with the civil laborer, exposed to healthy
influences of properly distributed air and sunlight, and to the regular
motions of a well-conducted life, is easy of solution to the inquiring
mind.
But when it relates to the soldier, subjected to strange and unhealthy
influences, the explanations involve much study, care, and research.
In the natural condition of man it is easy to determine how much food will
support life and sustain physical exertion. The dietaries of the public
institutions of different countries, the experiments of physiologists, and
the records of history give the data with sufficient clearness. As to the
amount of food required daily to repair the waste and wants of the human
organism, much depends upon the degree of muscular exertion and nervous
excitation, as well as the temperature of the season. In the alimentation
of armies scientific principles must not be disregarded. Food must be
considered as force; it must contain, not only material, but power. The
strength of men, says Baron Liebig, is in direct ratio to the plastic
matter in their food.
In determining the absolute quantities of nutrient substances required by
the system, Lehman observes that there are three magnitudes especially to
be considered.
The first is the quantity requisite to prevent the animal from sinking by
starvation. The second is that which affords the right supply of
nourishment for the perfect accomplishment of the functions, and the last
is that which indicates the amount of nutrient matter which may, under
the most favorable circumstances, be subjected to metamorphosis in the
blood. No one of the four classes, the carbohydrates, the fats, the
albuminous matters, and the salts, will answer the purpose alone, but all
must be employed together, and this invariable proportion according to the
local, and, therefore, variable waste of the system. These considerations
indicate how complicated the problem is.