osides may also serve as the mechanism for putting out of action of
harmful products which may appear in the tissues as the result of abnormal
conditions. These harmful substances may be rendered soluble by combination
with sugars and so transposed by osmosis to some other part of the plant.
The abnormally large percentages of glucosides which are present in certain
species of plants during unfavorable climatic conditions lends some support
to this view.

Finally, it may be assumed that easily oxidizable substances, such as
aldehydes and acids, are possibly protected against too rapid, or
premature, oxidation by being transformed into glucosides.

In general, it may be said that the glucosides seem to serve as the
regulatory, protective, and sanatory agencies of the plant mechanism.

BIOLOGICAL SIGNIFICANCE OF GLUCOSIDES

The bitter taste of glucosides and their almost universal presence in the
bark of plants undoubtedly helps to prevent the destructive gnawing of the
bark by animals.

Glucosides having either a strong bitter taste, or pronouncedly poisonous
properties, likewise undoubtedly serve to protect such important organs of
plants as the seeds and fruits from being prematurely eaten by birds and
animals. The common disappearance of these bitter substances as the seed or
fruit ripens adds to the attractiveness of the material for food for
animals at the proper stage of ripeness to provide for wider distribution
of the seeds for further propagation. Further, the very general occurrence
of these protective glucosides in many of the vegetative parts of plants
during the early stages of growth, followed by their disappearance after
the seeds of the plant have been formed, certainly serves to protect these
plants from consumption as forage by animals before they have been able to
develop their reproductive bodies. The lack of palatability, and even the
production of digestive disorders resulting from the eating of unripe fruit
may be due, in part at least, to the presence of protective glucosides in
unripe fruits and vegetables.

On the other hand, the almost universal presence of the brilliant pigment
glucosides in the external parts of flowers undoubtedly serves to attract
the insects which are biologically adapted to provide for the
transportation of pollen from one blossom to another and so to insure the
cross-fertilization which is so important in maintaining the vigor of many
species of