244 BOTANICAL GAZETTE [NOVEMBER 
1-400, there is increasingly greater digestion found (less starch 
remaining). The question immediately arose as to whether the 
result was inhibition or a retardation of the rate of digestion. This 
was answered by running two series of digestions over a period of 
four hours at the same temperature as in the previous tests. To 
DIASTASE 
SERIES 
Tl ic "1 ¢ T € Tl ¢ 
+ 2. =. a a me ic, eo eg 
tine 2 4 5 6 
2 
Fic. 7.—Time factor as related to starch digestion in presence of formaldehyde 
ixed 1-40 parts water: — of line indicates amount of starch remaining undigested 
(all conditions shown in duplicate); 1 cc. 0.5 per cent solution Merck’s diastase, 
10 cc, 25 per cent soluble starch solution, and 4 cc. formaldehyde used in tests (7), 
and a like amount water in controls (C); time periods in hours tests 1 to 6 respectively, 
1.25, 1.5, 1.75, 2, 3, and 4 hours. 
all the test-tubes of one series was added 1 cc. of the diastase solu- 
tion, to one-half of the tubes was added 4 cc. of formaldehyde 1-49, 
and to the other half (control) an equal amount of water. Ten cc. 
of the 25 per cent soluble starch solution was placed in all tubes. 
The second series was prepared in the same manner, except that 
formaldehyde of 1-320 concentration was used. Four test-tubes 
from each series were removed every fifteen minutes, two contain- 
