and also during
the germination process.

Injury to the plant tissue seems to be a necessary preliminary to the
functioning of the active components of the glucoside, except in the case
of the seeds. This leads naturally to the supposition that at least some of
these glucosides are protective or curative agents in the plant tissues.
This conception is further supported by the facts that many of the
non-sugar components of glucosides are bactericidal in character and that
the glucosides commonly occur in parts of the plant organism which are
otherwise best suited to serve as media for the growth of bacteria. Thus,
it is known that in the almond, as soon as the tissue is punctured,
amygdalin is hydrolyzed and all bacterial action is inhibited. Similarly,
the almost universal presence of glucosides containing bactericidal
constituents in the bark of trees insures natural antiseptic conditions
for all wounds of the outer surfaces of the stem of the plant. In fact, it
is easily conceivable that at least one of the reasons for the failure of
the processes of decay of plant tissues to set in until after the death of
the cells, is that during living, respiratory activity these antiseptic
glucosides are so generally present in the tissues.

Further, it has been fairly well established that the "chromogens," or
mother-substances of the pigments, which, under the influence of oxidase
enzymes, serve to regulate the respiratory activities of the plant are
essentially glucosidic in character. This, and other, functions of the
pigments, most of which are glucosides, will be discussed at some length in
the chapter dealing with the Pigments (Chapter VIII).

Many gaseous anaesthetics are known to have a marked effect in stimulating
plant growth. In a number of cases, it has been shown that the contact of
plant tissues with these anaesthetics brings about an interaction of the
enzyme and glucoside which are present in the tissue, with the consequent
hydrolysis of the latter, setting free its characteristic components. This
observation has led to the supposition that many of the organic
constituents of glucosides are definite plant stimulants, to which the name
"hormones" has been applied. There is considerable experimental evidence to
support this conception that glucosides may be the source of stimulating
hormone substances, which will be discussed more in detail in the chapter
dealing with these plant stimulants (Chapter XVII).

Gluc