A EI 
rdiet eae 
1914] 
DUGGAR AND DAVIS—FUCUS VESICULOSUS 421 
material), or in some cases with sea-water, using commonly 20 
per cent alcohol or 2-3 per cent toluene as a preservative. In 
general, toluene has proved the most satisfactory antiseptic. 
Тһе filtered extract was then precipitated with 95 per cent 
alcohol, the precipitate caught on a filter, washed with alcohol 
and dried. In a few cases the extract was used direct, and in 
certain respects the common practices were variously modified 
in the hope of detecting some simple explanation of the large 
number of negative results. 
The hydrolytic experiments were carried out in small Erlen- 
meyer flasks or test-tubes, and always in duplicate or tripli- 
cate. In addition, nearly every series was repeated once or 
oftener. А special effort was made to determine the presence 
of carbohydrases, and for this purpose weak solutions, usually 
0.5 per cent, of starch, glycogen, dextrin, saecharose, maltose, 
and lactose were employed in numerous tests. Хо reduction, 
or no change in the reducing value of the substrate, by the 
Fehling method, was found in any case in our final experiments, 
although in some cases a relatively large quantity of the sup- 
posedly enzyme-containing material was used. We found it 
necessary to purify the best dextrin obtainable by precipitation 
with 95 per cent alcohol from a strong aqueous solution. In the 
preliminary experiments, and chiefly with опе preparation, 
traces of reduction were found with glycogen, but in many later 
experiments this finding was not confirmed. 
Owing to the consistently negative results with these carbo- 
hydrates it seemed possible that there might be an adjustment 
of enzyme action in Fucus such that a relation of the mineral 
salts, as in sea water, might be requisite for highest action. 
Consequently the enzyme solution in one large series of experi- 
ments was diluted with double strength sea-water; in another 
case the material was extracted with sea-water; and finally, 
fresh material was used, making with it a diffusion in sea water. 
In every instance the result was negative. 
Another possibility then suggested itself, namely, that the 
presence of certain inhibiting substances might account for the 
absence of hydrolytic change. Accordingly, the effect of the 
Fueus material on the activity of taka diastase was determined 
in this way: To 10 grams of ground fresh material 100 cc. of 
5. 
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