1913] HAWKINS—MALT DIASTASE 267 
All water used was distilled from glass and condensed in a well 
seasoned glass condenser. The various pieces of apparatus coming 
in contact with the solutions or mixtures of the experiments were 
carefully cleansed in this water before use. 
Method 
The method here employed for determining the duration of 
hydrolysis is similar to that described by SHERMAN, KENDALL, and 
CLARK as the liquefaction method for estimating diastatic activity.® 
The exact procedure in the present study was as follows: A sufficient 
quantity of starch for the entire study was purchased at one time 
and thoroughly mixed. Of this material 2.5 grams were weighed 
out, placed in a porcelain dish, and by means of a glass rod rubbed 
into a suspension with a little water. This mixture was then diluted 
to a volume of 500 cc., boiled two minutes, and then strained through 
cheesecloth, thus making a o. 5 per cent starch paste, a homogenous 
Equid which flows freely and is easily measured from a burette. 
With the exception of a small amount used in preliminary tests, 
all the diastase for the investigation was purchased at one time 
and thoroughly mixed to insure uniformity. It was preserved 
in a glass-stoppered bottle and showed no signs of deterioration 
during the several months the study was in progress. A 2 per 
cent solution of this diastase was prepared in much the same 
manner as that employed in making the starch paste. Two grams 
of the dry material were first thoroughly suspended in a small 
amount of water and then diluted to a volume of 100 cc., after which 
the solution was filtered. Fresh diastase solution and also fresh 
Starch paste were prepared at the beginning of each experiment, 
to preclude the possibility of error resulting from the growth of 
Microorganisms. No antiseptic was used in the various mixtures. 
Stock salt solutions, sufficient in quantity for the entire study, 
were prepared at the beginning of the investigation, in concentra- 
tions of I-4 gram molecules per liter of solution, and from these _ 
the requisite dilutions were made. The iodine solution used in the 
tests was originally prepared in quantity sufficient for the whole 
°Suerman, H. C., Kenpatt, E. C., and Ciark, E. D., Studies on amylases. I. 
An examination of methods for the determination of diastatic power. # aod Am. 
Chem. Soc. 32:1073-1087. 1910; references to here 
