cereals, meats, fruit and vegetables all contain more or
less water or refuse that reduces their concentration, while in nuts we
find a compact form of almost pure food.

We are dependent on foods for the source of energy that is necessary to
perform our work and maintain our body temperature much in the same way
that a steam engine is dependent on the fuel supplied it to perform the
mechanical tasks assigned to it, and this fuel value of foods in turn,
depends on the amount of protein, carbohydrate and fat, particularly the
latter, that are present in the foods. At once we see, in our
concentrated nuts, a tremendous source of energy, provided that we can
digest these nuts and make this energy available.

Despite the fact, as revealed by chemical analysis, that in nuts we have
a source of protein and fat in a concentration rarely seen in foods,
there have been relatively few experiments to actually determine the
digestibility. Prof Jaffa at the California Experiment Station was the
first to make a comprehensive investigation along these lines. He made
extensive digestion tests on men using most of the more common American
nuts. His results, as reported in a bulletin of the U. S. Department of
Agriculture, indicated that nuts when they made up a substantial portion
of the diet, were well digested by those who ate them and gave no
intestinal disturbance or discomfort.

Nuts have had a reputation for indigestibility that was wide spread, not
only among people in general, but also among physicians and dieticians,
and even Prof Jaffa's clear cut experiments failed to dispell this idea
of indigestibility that had been empirically assigned to nuts. A few
years ago, a rather extensive series of digestion experiments were
inaugurated at Yale University in an effort to settle this question of
the indigestibility of nuts and also to test out some of the commercial
nut products to find what effect roasting, boiling, and other processes
that nuts are subjected to, had to do with the digestibility. Through
the courtesy of Dr Kellogg of Battle Creek, it was possible to follow up
these experiments with a series here at Battle Creek. It is the result
of these tests that I wish to speak of today. One word regarding the
method which is the conventional one for such experiments. The amount of
food eaten by the individual or animal is weighed at each meal and the
composition determined by chemical analysis. The intestinal output is
collec