64 
Pond. — The Incapacity of the 
grain. It may be said in this connexion that no one has proved that the 
diastase of the resting grain is in the endosperm as well as in the embryo. 
They do show (’ 90 , p. 507) that during formation of the seed the diastase 
increases. The proportion of diastase was estimated at three stages, 
namely : endosperm about one half developed, endosperm about two-thirds 
developed, endosperm fully developed but not ripe. This does not show, 
however, as stated by Green (’ 01 , p. 18), that the increase of enzyme takes 
place in the endosperm unless we assume that during the early develop- 
ment the embryo is too small to be considered. Brown and Morris do not 
state that they estimated the diastase present in the endosperm, but that 
they estimated the diastase in the grain when the endosperm was in 
varying stages of maturity. In this connexion they also state that a 
similar quantity of mature ungerminated grains yielded a similar quantity 
of cupric oxide. In this later test, however, the ungerminated seeds were 
allowed to steep, just how long is not stated, nor at what temperature, but 
if as long as in a preceding experiment (p. 496) the steeping lasted 24 hours 
and the temperature was not high enough to kill the embryo. Even if the 
steeping were only twenty-four hours the possibility of enzyme passing from 
the embryo to the endosperm is open 1 . On p. 507, they show that the major 
part of the soluble enzyme in the resting seed (after steeping) is located in 
the proximal half (embryo half), and that some also exists in the distal 
half. If it were not for the steeping a demonstration of enzyme in this 
distal half would be conceded. This paper of Brown and Morris may then 
be summarized as attributing diastatic capacity and vitality to the aleurone 
cells but as denying both to the amylaceous endosperm. 
Griiss (’ 93 , p. 288) found evidence of enzyme activity in the endosperm 
of maize from seedlings whose hypocotyls had elongated to six or seven 
centimeters. Since the aleurone layer and scutellum contain a much 
greater quantity of enzyme, he concluded that the diastase is secreted 
by these tissues and by diffusion from them penetrates the endosperm. 
Later, Griiss (’ 96 , p. 439) found that isolated endosperms of maize under 
sterile conditions of germination for twelve days gave a very positive 
reaction with the guaiac-hydrogen-peroxide test. A similar result was 
obtained with the endosperm of barley. If this guaiac test is to be accepted 
as reliable we must regard the capacity of the endosperms of maize and 
barley to generate enzyme independently of the embryo as demonstrated. 
To support this by further evidence the direct sugar test was made with 
Fehling’s solution. In this case, the barley endosperms were in moist sand 
four days, but no statement is made that sterile conditions were maintained. 
The glycerine extract from these endosperms after digestion for eighteen 
1 Brown and Escombe (’98, p. 11 ) concede the possibility of enzyme from the embryo 
penetrating the endosperm during steeping, and say that the embryo should be removed while the 
seed is still dry. 
