Embryo and Aleurone Layer of Hordeum. 
1197 
XV. Investigation of Amylase Content of the Tissues of 
Tropaeolum by Direct, Auto-, and Papain-digestion 
Methods. 
Determinations of the amyloclastic capacity of embryos (seedlings) 
and aleurone layers from barley at certain stages of germination having 
shown, contrary to the experience with ungerminated barley, that auto- 
and papain-digestions of these objects invariably gave lower values than by 
the direct method of digestion, at once raised the question whether the 
amylase present in the tissues of a typical phanerogamous plant, such as 
Tropaeolum , and presumed to consist wholly of the ‘ translocation ’ variety, 
would comport itself in a similar fashion. If so, then certain considerations 
might with justification be advanced regarding the possible nature and con¬ 
ditions of existence of the pre-existent amylase or its possible antecedent in 
the inner endosperm of the grain of barley. 
A quantity of freshly gathered plants of Tropaeolum were procured, 
dissected into petals, stems, and roots, 1 desiccated for forty-eight hours at 
30° C., and afterwards separately investigated for amylase by the direct, 
auto-, and papain-digestion methods. 
Experimental and corresponding control digestions were carried out as 
follows:— 
The desiccated material was first finely pulverized in a mortar, then 
passed through a finely-meshed horsehair sieve, and quantities of material 
taken from the bulk of 0-3 grm. were placed in each of a series of conical 
Jena flasks and afterwards 10 c.c. of either plain distilled water (auto¬ 
digestion) or of a 0*5 % or 1 % solution of papain (papain-digestion) were 
pipetted into each flask. 
The flasks and their contents were then placed in a thermostat at 
30° C., and after the addition of an antiseptic and tightly corking, the 
predigestion was continued for twenty hours. 
The contents of the control predigestions were then arrested by 
boiling, cooled, brought to the temperature of the thermostat (30° C.), a 
fresh addition of antiseptic made, and 15 c.c. of soluble starch solution 
(equivalent to 25 c.c. at 3 grm. starch solids per 100 c.c. of solution) were 
added to both experimental and control flasks, and the starch digestions 
thus established were continued for twenty hours at 30° C. 
A similarly constituted series of experimental and control digestions 
(direct digestions) were carried out simultaneously with the above by 
adding directly 25 c.c. of 3 % starch solution to each 0-3 grm. of finely- 
1 Brown and Morris: Chemistry and Physiology of Foliage Leaves. Journ. Chem. Soc., 
1893, vol. 63, p. 634. After desiccation the stock material was conserved in a desiccator over 
H a S 0 4 . 
41 
