Uron STARCH-CONVERTING POWER OF. TAKA DiasTasE 63 
#/1,000 nearly halving the amount of sugar. Chloral hydrate is 
injurious, though a slight acceleration is given at a dilution of 
2/1,000. Peptone accelerates most at 2.5 per cent., and _ still 
markedly at ,!, per cent. Asparagin accelerates strongly at 2/20, 
and still slightly at 2/1,000. 
Many observers note the detrimental action of alkalies on cer- 
tain diastases. Chittenden & Ely * note a decrease of one third 
in the amount of sugar due to 1 per cent. of sodium carbonate. 
Langley & Eves + found 0.0015 per cent. sodium carbonate checks 
starch transformation, and potassium hydroxide checks more still. 
They note that the rate of decrease in the effect of weaker con- 
centrations of alkalies is slow compared to acids. 
Without exception, in my work the alkalies seemed detrimen- 
tal ; slightly so even up to x/10,000 dilution. Sodium, potassium 
and ammonium seem slightly less injurious than calcium. In no 
case was there any acceleration in the presence of an alkali. 
(Compare Table IV.) : 
The metals are in general injurious. (Compare Table IV.) 
Iron allowed no action at n/10; being more injurious than copper, 
which did not entirely stop conversion until a 7/4 concentration 
was reached. Copper sulphate and copper chloride acted very 
much alike, both giving a slight acceleration at #/10,000. Silver 
was very detrimental indeed. No conversion took place below 
m/10,000, and only a slight amount at 7/100,000. Zinc nitrate and 
barium chloride gave a peculiar curve, similar to that of some of 
the acids, but at 7/100 barium chloride just reached the normal, 
and inhibited at 7/1,000, while zinc nitrate accelerated transforma- 
tion at 7/100 and inhibited action at 7/1,000. 
The work of Clark t on the decrease of toxicity of mercuric 
chloride by the addition of other chlorides suggested that a similar 
series of experiments be tried on taka diastase. 
In my experiments a x/5,420 solution of mercuric chloride was 
used, and to that varying amounts of calcium chloride were added. 
The results were very striking, as is shown in Table VI. Here 
the plain line represents the action of the solution of constant 
/* Chittenden & Ely, Z. c. 
» Langley & Eves, /. c. 
< Clark, Journal of Physical Chemistry, 5: 289. 
~ 
