ese studies
have not as yet been brought to the stage of final conclusions, and the
ideas presented must be considered as suggestive rather than as conclusive.

VITAMINES

"Vitamines," as contrasted with "hormones," are supposed stimulants of
synthetic metabolic processes, or accelerators of growth, rather than of
degenerative processes.

The term "vitamine" was first used to designate the substance, or
substances, which must be present in the diet of animals in order that the
animal organism may grow. Absence of these substances from the food of the
animal results in the stoppage of growth of young animals and in various
so-called "deficiency diseases" (such as beri-beri, scurvy, polyneuritis,
etc.) of adults. This means that the animal organism is altogether unable
to elaborate its own vitamines, and extended investigations have indicated
that the vitamines necessary for animal uses are wholly of plant origin.
The name "vitamine" was first used because it was supposed that these
substances are chemical compounds of the amine type and, since they are
necessary to normal life processes of animals, the name "vitamine" seemed
to represent both their chemical character and their functions. Later
investigations have caused doubt as to the accuracy of the first belief as
to their chemical nature, and various other names have been suggested for
the general group of substances which have the observed beneficial
effects; while such specific names as "fat-soluble A," "water-soluble B,"
etc., have been used to designate individual types of these accessory food
substances. However, the term _vitamine_ is such a convenient one and is so
generally recognized and accepted that it will probably continue to be
used, at least until some more definite knowledge of the nature and
composition of these growth-promoting, disease-preventing, and
reproduction-stimulating food constituents is obtained.

The following definition of the term "vitamines" gives a satisfactory
conception of the nature and functions of these substances, so far as they
are yet known. "Vitamines; constitute a class of substances the individuals
of which are necessary to the normal metabolism of certain living
organisms, but which do not contribute to the mineral, nitrogen, or energy
factors of the nutrition of those organisms." As sub-groups of the
vitamines, there have already been recognized the growth-promoting,
fat-soluble A; t