1182 Stoward.—Amyloclastic Secretory Capacities of the 
re-steeped in water for twenty-four hours. This steep water on concentra¬ 
tion to small bulk acquired a faint but obvious blue colour, and confirma¬ 
tory evidence of the presence of copper was obtained by testing the faintly 
acidified solution with potassium ferrocyanide. 
It is evident, therefore, that in spite of what appeared to be very 
thorough washing, complete removal of the copper salt, or reduction of its 
amount to such small limits that its toxicity may be regarded as negligible, 
is not accomplished with any degree of certainty. It seems to be highly 
probable that copper sulphate interacts with a cellulosic or pectinous con¬ 
stituent in the seed coverings, forming a loose compound which possibly 
slowly dissociates in the culture medium. Although the salt probably 
exercises its toxic action on the amylase which diffuses from the objects into 
the culture medium during the progress of the culture experiment, the 
demonstration of such action is only rendered evident when the medium is 
digested with soluble starch. 
The uncertainty associated with the use of copper sulphate as a steep 
reagent leads to its abandonment in favour of absolute alcohol. When air- 
dried barley seeds are steeped in this reagent for 24-48 hours, abstraction 
of water and certain extractions from the seed coverings take place, but 
there is no evidence of penetration of the reagent into the interior of the 
seed, nor does the steeping of barley seeds in this reagent obviously impair 
their germinative capacities. 
XIV. Investigation of Material by the Auto- and 
Papain-digestion Methods. 
The recent work of Ford and Guthrie 1 shows that the amylolytic 
activity of ungerminated barley varies considerably according to the method 
of preparing the extract. Their results indicate that the extract of a given 
barley prepared by the auto- or papain-digestion methods described in their 
paper exhibits an increase of amylolytic activity over and beyond that 
yielded by the same barley when the method of preparation adopted is 
the customary or direct one usually employed. Thus, when a definite 
weight of ground barley substance is predigested under definite time and 
temperature conditions, either with plain distilled water, aqueous solutions 
of certain neutral inorganic salts, certain organic substances (notably amino 
acids), or with solutions of active (boiled) or passive (unboiled) papain, and 
the filtered extracts derived from these predigestions are digested with 
soluble starch under otherwise identical experimental conditions, they 
exhibit a much higher amylolytic power than do aqueous extracts prepared 
from the same barley by the customary method of short extraction. 2 
1 Journ. Inst. Brewing, 1908, xiv, p. 61. 
2 The authors state that these various substances do not directly stimulate amylolytic activity 
