Self-digestion of the Endosperm of some Graminaceae. 453 
an easily soluble sugar, already formed, at first comes out from the endo- 
sperm, and afterwards the sugars formed by the decomposition of starch. 
Sugars, and salts like KN0 3 , CaCl 2 , and KC1, at higher concentration 
than 5 per cent., stopped the evacuation in Puriewitsch’s experiments. He 
explains this arrest by assuming a partial plasmolysis, which impedes the 
exosmosis of substances from the cell, a view which conflicts with several 
experiments made with yeast, in which plasmolysed cells even secrete 
invertase. 1 
Besides, Griiss had already made use of plasmolysis in order to cause 
exosmosis of diastase from germinating seeds. Also Puriewitsch has not 
taken into account that certain other salts, especially calcium phosphate, 
and even plaster itself, accelerate the activity of amylase. 
The chief argument for vitality brought forward by Puriewitsch is the 
action of narcotics. According to our author, chloroform and ether prevent 
the evacuation of Maize endosperms. Of less value for the demonstration 
of the vitality of the endosperm cells is the observation of Puriewitsch that 
endosperms which are not well aerated do not empty. Indeed, if by chance 
we find amylase in the resting seed, chiefly in the form of proenzymes 
which become active by oxidation during germination, we have a similar 
result. On the latter point one remembers that some years ago Baranetzky 
\’78), Wortmann (’82), and Detmer (’83) proved that free oxygen is neces- 
sary for the formation of diastase in seeds. In short, the very experiment 
which ought to be the most convincing yields to Puriewitsch a result contrary 
to his views. Various living reserve organs after artificial evacuation fill up 
again if placed in concentrated nutritive solutions ; but with starch and 
horny endosperms this did not succeed. Notwithstanding this, Puriewitsch 
and Pfefler (’97) maintain that amylaceous and horny endosperms are alive, 
and that their evacuation is a purely vital process. 
Brown and Escombe (’98, p. 14) have confirmed the fact that Barley 
endosperms soaked in chloroform water for twenty-four hours did not show 
any solution for several days, at the end of which time they were invaded 
by moulds and bacteria, while non-chloroformed endosperms showed a con- 
siderable evacuation. The authors observe that in this case the solution 
was sub-aleuronic, and they endeavour to demonstrate that only the 
aleurone cells can be alive. 
Moreover, the cytological study of the endosperm cells indicates to these 
authors that, while the cells of the aleurone layer have a well-defined nucleus 
and all the usual marks of living cells, the starch-containing cells of the endo- 
sperm have deformed nuclei and a structure like that of aged cells. Brown 
and Escombe also deny the auto-digestive capacity of the amyliferous 
cells, because Barley endosperm, deprived of embryo and aleurone layer, and 
kept under conditions favourable for germination and for the removal of the 
1 Pantanelli (’06), p. 16 . 
