1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 795 
experiments, it was desired to know which, if any, were the 
most favorable substrates for the diastases of the algae. The 
action of diastase from Ulva lactuca was taken as an index. 
Potato, arrowroot, wheat, corn, and soluble starch, as well as 
inulin, were made up in 1 per cent concentrations in the man- 
ner previously described. To 50 ce. of each of these sub- 
strates were added 10 ce. of a diffusion of an alcohol precipi- 
tate from a water extract of dehydrated Ulva lactuca. Two 
per cent toluene was added as an antiseptic, and the flasks 
maintained at a temperature of 35°C. for 30 days. The re- 
sults of the experiments are given in table m1. 
The data show but slight differences in the rate of digestion 
of the starches with the exception of corn starch, and the 
reason for this is not clear. One would expect it to be due to 
some impurity in the starch rather than to an inherent dif- 
ference in the granule. The action on inulin was so slight as 
not to warrant the assumption of hydrolysis due to inulase. 
The action of an extract of Ulwa lactuca upon various carbo- 
hydrates.—A series was arranged using a ‘‘diffusion- 
extract’’ from Ulva lactuca with the following substrates: 
potato starch, dextrin, glycogen, sucrose, maltose, and lactose. 
Ten ce. of the ‘‘diffusion-extract’’ were added to each flask 
with 50 ce. of substrate, 2 per cent toluene used as an anti- 
septic, and the flasks maintained at a temperature of 35°C. 
for 30 days. The data are given in table m. 
TABLE III 
THE ACTION OF AN EXTRACT OF ULVA LACTUCA UPON VARIOUS CARBOHYDRATES 
Sugar as glucose in 5 ce. 
Substrate mss: 
15 days 30 days 
Starch Wctirdecukra seis 10.20 15.50 
Dextrose sehen 6.30 9.95 
GIN COEONs oonosodonedeous 2.25 3.50 
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The two polysaccharides, starch and dextrin, are very 
readily attacked even though the action is slow. Glycogen, 
which is hydrolysed by most diastatic enzymes with about the 
