Self-digestion of the Endosperm of some Graminaceae. 45 1 
increasing in the endosperm ; but the quantity of ferment produced by the 
scutellum is always much larger. 
With great skill Pfeffer (’93) and his scholar Hansteen (’94) approached 
the subject. They did not exactly accept Van Tieghem’s statements as to 
autonomous evacuation occurring only in oleaceous seeds and not at all in 
amylaceous ones. Van Tieghem had not provided for the elimination 
of the products of digestion, the accumulation of which would entirely 
prevent further digestion, as might be easily foreseen, by the principle of 
mass-action which governs all reactions in chemical equilibrium. 
In so far as reversible reactions are concerned, as soon as the products 
of decomposition have reached a certain concentration the velocity of 
reaction in the sense of decomposition tends to become zero, while the 
inverse reaction, the reconstitution of starch, becomes perceptible. 
By Pfeffer’s advice, Hansteen, in order to obtain the rapid removal 
of the starch dissolution products, fixed isolated endosperms on small 
plaster columns immersed almost to the top in a sufficient quantity of 
water. The endosperms were well aerated, and the starch dissolution pro- 
ducts, issuing from the endosperm from the wounded side (whence the 
embryo had been cut off ), diffused through the plaster into the surrounding 
liquid. In this manner a complete evacuation was secured, with removal of 
the reducing sugar from the starchy endosperms of Barley, Wheat, and 
Rye ; the process was almost complete in Maize, in the horny endosperm 
of Date (hemicellulose), and in other reserve tissues. If the quantity of 
water was limited, the evacuation was arrested almost as soon as it began. 
From these results Hansteen concluded that even mealy and horny 
endosperms are alive, only a necessary condition for their emptying is the 
continuous export of the products of dissolution. 
Griiss also observed (’95) that the products of the diastatic decom- 
position of starch paralyse the amylase action. 
Linz (’96) repeated these experiments with Maize endosperms, putting 
them into a moist space, but so that nothing could be sent off, and he found 
an increase of diastase . 1 The same result was obtained by keeping endo- 
sperms for five days on damp blotting-paper. 
Griiss (’96) found that sterile endosperms of Maize, kept for twelve 
days under conditions comparable to germination, gave a very positive 
reaction with hydrogen peroxide and guajacum. He obtained a similar 
result with Barley endosperms. If the guajacum test was available for 
demonstrating diastase, it could be argued that Maize and Barley endo- 
sperms form enzymes independently from the embryo. But the guajacum 
test is only workable for the oxidase, whose presence is known in the flour 
as well, that is, in evidently dead endosperm material. 
By placing endosperms on little plaster columns in 80 c.c. water, Linz 
1 Brown and Morris had found that, under such conditions, diastase does not increase. 
