in a composite article of food are in
question, divers researches must be carried out before giving a final
judgment.

If a more or less complex article of food is in question, before
considering it as a good nutriment, its centesimal composition, or its
immediate composition, should be established; its theoretic calorific
power should be known, and it should be measured if this has not yet
been done.

Besides the calorific yield thus estimated _in vitro_, the real
utilisation in the human organism of articles of food alone or mixed
with other foods should be determined, taking simultaneously into
account their effects, whether tonic, stimulating or depressing.

From a different point of view it is no longer allowable to neglect
before judging whether such and such a nutritive substance is
advantageous, the valuation of what we have called, with Prof.
Landouzy, the economic yield--that is to say, the price of the
energy, provided by the unity of weight of the article of food.

It is only in reviewing "vegetal" substances, taking these divers
titles into consideration, that we shall be justified in attributing
to the practice of "vegetalism," integral or mitigated, its definite
value.

IV

Only a few years ago, when Schutzenberger, emulator and forerunner of
Fischer, Armand Gautier, Kossel, first disjointed the albuminoid
molecule, to examine one by one its divers parts, the composition of
the various albumins was very little known. Whether, therefore,
albumins of the blood, or those of meat or eggs, were in question,
these bodies were hardly ever separated, except through physical
circumstances, amongst others by constant quantities of different
coagulation. As to the centesimal formula and the intimate structure
of the different protoid substances, they could be considered as
closely brought together.

From this fact, the physiological problem of the utilisation of
albumin was simpler. No matter which article of food contained this
albumin, its nutritive power by unity of weight remained the same. At
the present time the number of albumins is no longer limited. It is
not now physical characteristics founded difficult separations which
arbitrarily distinguish those bodies from each other. The
individuality of each of the albumins results from its formula of
deterioration, under the influence of digestive ferments, or of
chemical bodies acting in a similar way, as do mineral acids and
alkalis. For want of co