410 BOTANICAL GAZETTE [JUNE 
changes occurring in a single kind of normally germinating seed, 
and thus to contribute to the facts of germination in general, and 
at the same time to provide a possible basis of comparison for some 
of the still unsolved problems of delayed germination and after- 
ripening. 
Historical 
DETMER (9) in 1880 presented a comprehensive summary of the 
work done up to that time by himself and others on the physiology 
of germination, and in the section dealing with the metabolism of 
storage substances he outlined the general facts in regard to the 
appearance, in various parts of the embryo, of starch, sugar, and 
nitrogenous compounds following the breaking down of reserve 
substances. Brown and Morris (5), working on barley, found that 
the first visible change is the appearance of starch in the embryo, 
and localized the secretion of diastase in the epithelial cells of the 
scutellum. They also stated that the endosperm is a dead tissue 
incapable of self-depletion, although a few years later, after further 
work, BRowN and Escomse (4) concluded that the aleurone layer 
is a living tissue by whose activity depletion of the endosperm 
might occur in the absence of the embryo. HansTEEN (12) and 
Purtewitscu (17), however, maintained that the endosperm is 
capable of self-depletion provided the hydrolytic products are 
removed. The later work of Miss Bruscut (6) harmonizes these 
divergent views by showing that while self-digestion can occur in 
various kinds of grains, it does so to such different degrees that 
earlier investigators, working each upon a single form only, reached 
contradictory conclusions. 
Of more direct bearing upon the subject is the work of LECLERC 
and BREAZEALE (14), in which by macrochemical analyses 4 
quantitative study was made of the effects of different culture 
media upon the amounts of various organic and inorganic sub- 
stances found in the several portions of the wheat seedling at 
different stages of germination. One of the latest contributions 
to the question of chemical changes during germination is that of 
Miss E.ckERsoN (11), who finds that in light-sensitive seeds active 
hydrolysis of hemicelluloses, fats, and proteins in the endosperm 
occurs in both light and darkness, but that in the light this process 
