Self-digestion of the Endosperm of some Graminaceae. 457 
It is to be remarked that Puriewitsch performed his narcotic experi- 
ments only with Cinquantino Mais. For the rest, evacuation in Barley goes 
on much more rapidly than in Maize, and, as the cell-walls are attacked 
before the starch, it would be difficult to hold that a tissue which no longer 
exists as a tissue dissolves its reserves by its own vital activity — a con- 
viction that has already taken possession of Brown and Morris. 
In this case also search was made for a pro-enzyme which would 
become active even in aseptic autolysis at low temperatures. The con- 
clusion was reached that a zymogen does exist, becoming active in the 
presence of oxygen or of a weak acid — e. g. the endosperm juice gave, 
directly after trituration, for amylase 3 mg. CuO, and after twenty-two days 
of aseptic maceration 73-2 mg. The juice from scutella and embryos gave 
in the first test 4 mg., and in the last 80-3 mg. CuO. 
One does not wish to say that all the cells of the Barley endosperm 
must be dead from the beginning of germination. Microscopic researches 
on vitality showed that if a residue of vitality does exist in the endosperm, 
we can find it only in the immediately sub-aleuronic tissue, because only 
there (with difficulty on account of the accumulation of reserve material) 
can we find a trace of plasmolysis, and because only there can we see, after 
appropriate staining, vestiges of nuclear substance, though we cannot speak 
of a well-defined nucleus. 
Wheat. 
In Wheat I was able to get complete emptying of isolated endosperms 
in free air. In the chloroform atmosphere evacuation could not proceed, 
and the whole endosperm became very hard, so that in this case chloroform 
seems to stop both the cytasic and amylasic actions. The behaviour of the 
individual cells towards plasmolytic agents and stains would demonstrate 
that they do not renew their vitality during germination. No trace of 
nuclei could be made out in the endosperm except in the aleurone cells. 
The solution of reserve material does not prove the vitality of this tissue, 
because I have been able to show, by the usual methods, that the resting 
seed contains pro-amylase which becomes active under the influence of 
oxygen and dilute acids. E. g. in the first amylase test only a trace 
of CuO was found, while after twenty days (at i8°C.) 123-92 mg. CuO were 
obtained for 5 c.c. endosperm juice. The scutellum and embryo juice gave 
in the first test only traces of CuO, and in the last 40-26 mg. CuO. 
In these experiments no account had been taken of the small volume 
that the scutellum and embryo occupy in the seed, so that juices which had 
been made with the same amount of water or dilute glycerine were more 
concentrated in the case of the endosperms than of the scutella and 
embryo. Therefore one could not exactly estimate the ratio of increasing 
amylase between the two parts ; inasmuch as, the endosperm extracts being 
