65 
Date Endosperm for Self-Digestion. 
hours with i per cent, starch-paste and diluted gave a mixed solution 
5 cc. of which reduced i-8cc. of Fehling’s solution. A similar solution 
from normally germinated seeds reduced 1-9 cc., while such a solution from 
ungerminated seeds reduced i*i cc. This experiment is not conclusive, for 
the following reasons : — It is not positively stated or implied that the endo- 
sperms remained sterile ; the starch-paste may have contained a little sugar ; 
the digestion during eighteen hours may not have been free from the 
influence of organisms, as no statement of such precaution is made ; ten 
hours is the limit of safety without antiseptics at 37 0 C. ; the end reaction 
with Fehling’s solution is not accurate to even 1 cc. with mixed solutions 
containing proteid and starch in varying stages of alteration ; the small 
differences of -i cc. between the reducing power of the solution from isolated 
endosperms and of the solution from normally germinated seeds is sus- 
picious. Moreover, if the endosperm contains reducing substance an 
extract from material soaked four days would probably contain more 
of such reducing substance than a similar extract from dry resting endo- 
sperms even though the time of extraction in both cases were equal. 
In the case of the date-seed, Griiss (’ 96 , p. 421) found the resting 
endosperm to be practically free from enzyme by the guaiac-hydrogen- 
peroxide test. In the endosperm of germinating seedlings (’ 96 , p. 422) 
he found by test isolated blue spots indicating the local generation of 
enzyme independently of the embryo. But concerning this it may be said 
that as long as the cotyledon was present during germination such a test 
cannot be regarded as demonstrating independent activity by the endo- 
sperm. In summarizing the work of Griiss we may say that the autolysis 
of the endosperm in the cases of barley and maize is proven only in so far 
as the guaiac-hydrogen-peroxide test is specified for the presence of hydro- 
lizing enzymes. In the case of the date there is little approach to con- 
vincing evidence. 
Hansteen (’ 94 , p. 426) regards Van TieghenVs conclusion, concerning 
self-digestion as occurring in oily seeds but not in amylaceous seeds, as 
untenable. First, because Van Tieghem made no provision for the escape 
of the products of digestion. The accumulation of such products in starchy 
seeds would soon inhibit further digestion. Such inhibition in the case 
of oily seeds would, however, occur much later, because the oil is first 
changed to transitory starch and considerable disappearance of oil might 
be noted before the accumulation of the products of starch transformation 
would inhibit further digestion. Second, because Hansteen considers him- 
self to have demonstrated that isolated endosperms of barley and corn 
under sterile conditions of germination favourable to the escape of digestion- 
products are self-digesting to a considerable extent, and that actual de- 
pletion and corrosion of the grains may be noted. The surrounding water 
into which the digestion-products diffuse becomes reducing to Fehlings 
V 
