SECRETION OF DIASTASE BY PENICILLIUM CAMEMBERTII 237 
sidered impracticable to determine the amount of starch digested by 
finding the amount of the reducing sugar produced. A part at least 
of the sugar produced by the action of diastase is used in the meta- 
bolism of the fungus. Furthermore, it has not been demonstrated 
that Penicillium camemhertii changes to glucose all of the maltose 
formed by the action of its diastase on starch. An alternative method 
might be the following: to determine the reducing value of a part of 
the solution; to hydrolyze the carbohydrates present in the same 
volume of the solution by boiling with hydrochloric acid, and to 
determine the reducing value of this portion. The difference between 
these two determinations should be the value of the nonreducing 
carbohydrates of the solution expressed in terms of glucose. This 
method was considered impracticable because of its tediousness and 
because of the uncertainty of the nature of the reducing sugars formed 
from starch by Penicillium camemhertii. 
An attempt was therefore made to evolve a different method of 
determining diastatic action. It is known that starch and a part 
of the dextrins are insoluble in a concentrated aqueous solution of 
alcohol. The sugars formed as a result of the action of diastase on 
starch, and perhaps part of the dextrins, are soluble in such a solution. 
This fact was consequently employed in the new method of deter- 
mining diastatic action here described. 
As finally used the method is as follows: By means of a pipette, 
20 cc. of the medium are added, slowly and with constant shaking, 
to 70 cc. of 95 percent alcohol, which is acidified with i cc. of hydro- 
chloric acid (sp. gr. 1.18-1.19).^ This is allowed to stand over night, 
then filtered through a Gooch crucible, dried at 105° C, cooled in a 
desiccator over anhydrous CaCU, and weighed. This method gives 
us directly the amount of starch and dextrins which have not been 
digested to the point at which they are soluble in 73 percent alcohol.'' 
The applicability of this method to the determination of diastatic 
action might be questioned. It was considered necessary, therefore, 
to compare the measurement of diastatic action by this method with 
the measurement of diastatic action as found by the amount of re- 
ducing sugar produced. This comparison was made by determining 
the influence of the quantity of diastase on starch digestion, and the 
influence of time on the digestion by diastase. 
^ Weaker solutions of hydrochloric acid than this may be used. See below. 
^ A mixture of 70 cc. of 95 percent alcohol + 21 cc. of nonalcoholic liquid is a 
solution of about 73 percent alcohol. 
