58 KELLERMAN: EFFECTS OF CHEMICAL AGENTS 
The effect of increasing the amount of diastase, the starch 
solution remaining constant, is to increase the rapidity of transfor- 
mation, though not in proportion to the increase in the amount 
of enzyme. This is shown in Table I, in the three series that 
were allowed to act seven, five and three hours respectively. 
Here the abscissae represent the amounts of a 0.25 per cent. solu- 
tion of taka diastase used in each case. 
In the following experiments * the different chemical agents 
were prepared each in 100 c.c. of a sterilized I per cent. potato 
starch solution, and placed in thoroughly sterilized and well-stop- 
pered bottles. Usually seven different substances, each with four 
different concentrations, were tested at the same time. These, 
together with four to six check bottles, containing 100 c.c. of pure 
starch solution — to make certain the relative determination of the 
effects of the various compounds — constitutes a series. 
To each bottle of such a series was added 2 c.c. of a 0.25 per 
cent. solution of taka diastase. All were then placed in a ther- 
mostat and kept at 43° C. for about twelve hours. The thermo- 
stat was light-proof, and therefore precluded any inaccuracy due 
to the breaking down of the enzyme by light, or its acceleration 
caused by the action of light filtered through glass.+ After incu- 
bation the entire series was placed in an autoclave and heated 
rapidly to 110° C. This temperature effectually destroys the 
diastase and any zymogen that might be present, as a preliminary 
experiment clearly showed. 
Care in handling and setting up a series, and sterilization of 
everything used avoided any inaccuracy due to bacterial action, as 
indicated by numerous checks. 
The relative amounts of sugar in the different bottles were de- 
termined volumetrically against 2c.c. of Fehling’s solution, as be- 
fore. Whenever the chemical agent present interfered with accu- 
rate determinations, either by hydrolyzing the starch or by interfer- 
ing with the reaction of Fehling’s solution, the agent was removed 
or so changed as to be innocuous before heating to destroy the 
enzyme. Thus acids were neutralized, the copper salts precipitated 
out as hydroxides, etc. 
* In all cases in these experiments Eimer & Amend’s C. P. materials were used 
+ J. R. Green, Transactions Royal Society, 188, B: 167. 
