Date Endosperm for Self-Digestion. 67 
if occurring in the endosperm under conditions which would permit us 
to say that the embryo had no influence. Sablon notes the interesting 
fact that during germination the relative quantity of oil in the undigested 
portion of the endosperm remains about constant, 7 to 9 per cent. He 
also finds that the sugar and dextrin also remain about constant, but that 
the resting grain contains a little more because it has not lost by exosmosis. 
He concludes that the enzyme from the embryo does not penetrate the 
endosperm. 
Puriewitsch (’97, p. 13) studied the depletion of the date endosperm, 
and concluded that it is capable of auto-digestion. How such a conclusion 
could be drawn from the data he has recorded cannot be understood. 
In the first place he allowed the seeds to germinate in sand until the 
radicle was from 3-7 cms. long. This would require, according to tempera- 
ture, from two to four weeks, and enzyme from the embryo would certainly 
pass into the endosperm. Newcombe (’99, p. 68) found an enzyme in the 
endosperm during later germination, and if my own conclusion is correct, 
that an enzyme cannot be detected in the resting endosperm, it is evident 
that such diffusion must occur during germination?. Moreover, Puriewitsch 
does not record actual evidence of digestion. He found merely that the 
‘culture fluid’ was reducing to Fehling’s solution. This is not significant, 
because the resting endosperm contains reducing substance, and further 
the tannin present would give the same reaction. As a matter of fact his 
record furnishes more evidence for a negative conclusion, because in micro- 
scopic sections of his material he did not find any notable difference between 
test objects and controls. How could auto-digestion be attributed to a 
tissue which, after thirty-six days at 27° C., showed no evidence of dissolu- 
tion as compared with controls? Further he regards the endosperm as 
living matter capable of initiating and continuing vital processes ('97, 
p. 16). 
In ’98, after the researches of Hansteen and Puriewitsch, which are 
regarded by Pfeffer (’97, p. 613) as demonstrating that the endosperms of 
barley, maize, and date are capable of self-digestion, Brown and Escombe 
(98, pp. 3-24) undertook a reinvestigation of the work of Brown and _ 
Morris (’90, p. 458). After quoting the general conclusions of the latter _ 
as follows : ‘ Although the peripheral layer of the endosperm, the so-called _ o 
aleurone-layer, undoubtedly consists of living cells, no evidence could be 
obtained of the existence of any residual vitality in the amyliferous cells 
which constitute by far the greater portion of the endosperm,’ they state — 
that there is a general agreement in the work of Hansteen, Pfeffer, Griiss, 
Ce a ee, * ho eee + overlooke 
1 Puriewitsch makes a brief stat t me 
but he does not show that the error was actually avoided. His gatement 1 seems ns to refer to the a 
cereal endosperms especially, and cannot be applied to the date, because in the text mage? of as 
manipulation in the date experiments he states that the seeds were allowed to germinate. 
F 2 
