8i3 
Embryo and Aleurone Layer of Hordeum. 
lized in CuS 0 4 solution, it was surmised that this reagent, manifesting its 
influence more especially during the digestion with soluble starch, consti¬ 
tuted a probable disturbing factor. This suggestion was, however, negatived 
by similarly established cultures with embryos derived from seeds which 
had been steeped successively in absolute alcohol and water yielding equally 
low results. 
Asparagin and KH 2 P 0 4 are amphoteric substances, and, as shown by 
Ford 1 and Ford and Guthrie, 2 such substances may function in a protective 
manner towards barley amylase by maintaining the (i) extraction or 
(2) digestion medium in a state of comparative neutrality. 
Whether this holds during the different phases of culture on nutrient 
substrata in the experiments to be described presently, or whether they 
serve mainly as nutritive substances and partly by stimulating secretory 
activity, lies beyond the actual scope of this inquiry. 
The fact that in general enhanced secretion of amylase by the embryo 
follows on their use warrants their employment. 
The results given in the following table may be taken as typical 
examples of possession by the embryo of this secretory capacity, of its 
variation with different concentrations of asparagin, and of its progressive 
increase with prolongation of the culture period. 
TABLE I. 
Cultures of Embryos on Asparagin-Mineral Salt Medium. 
Concentration 
of asparagin Duration of Digestion 
per 100 c.c. culture. period, 
of sohition. 
Amylase in culture medium 
per 20 embryos (equivalent 
to mg. of Cu . 
(African barley.) 
Experiment 1. 
Seeds 48 hours absolute alcohol, 48 hours water. 
1-65 
4 days 
2^ hours 
20-1 
1.10 
V 
}> 
16.1 
o*55 
30*5 
0*055 
?> 
32.2 
(African barley.) 
Experiment 2. 
Seeds 48 hours CuS 0 4 . 
1.65 
8 days 
2§ hours 
50*9 
1.10 
>> 
3 i *9 
o*55 
>} 
>5 
75*7 
0.055 
>> 
95*9 
(African barley.) 
Experiment 3. 
Seeds 48 hours CuS 0 4 , 
24 hours water. 
o*55 
8 days ' 
20 hours 
5-7 
(asparagin only) 
The results show clearly, as already demonstrated by the work of 
Brown and Morris, that the barley embryo undoubtedly possesses the 
power of secreting amylase. 
1 Journ. Soc. Chem. Ind., 1904, xxiii. 414; Journ. Chem. Soc., 1906, lxxxix. 76. 
2 Journ. Inst. Brewing, 1908, xiv, i. 61-87. 
3 H 
