1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 807 
in salt water, with toluene to keep down bacterial action. 
Very slight, if indeed any, gelatinization is evident with the 
frond placed in salt water, while that in fresh water begins 
to gelatinize immediately. It is also a well-known fact that 
in histological or cytological work with these forms, the kill- 
ing fluids must be made up in sea-water or water containing 
a high percentage of salts, else gelatinization interferes. 
These facts, together with the apparent absence of cellulase 
and cytase, tend to show that the galactan and pentosan 
groups are always present as final condensation forms of their 
particular ‘‘generic’’ carbohydrate line, and that sliming in 
the marine algae, at least, is the result of the adsorption of 
water by these already existing carbohydrate groups. 
DISCUSSION OF RESULTS OF CARBOHYDRASE EXPERIMENTS 
It is seen from the data presented in the foregoing tables 
that carbohydrases in the algae, at least those that can be 
isolated by standard methods, are very few. Furthermore, in 
all cases where such carbohydrase action is evident, it is 
limited to the polysaccharides—starch, dextrin, laminarin, 
and glycogen. In no case were the disaccharides hydrolysed. 
As groups, the ‘‘greens’’ are more active than the ‘‘reds,’’ 
while of the ‘‘browns,’’ Laminaria is the only form in which 
carbohydrate action is demonstrable. Moreover, the action 
here is extremely slow and is limited to starch, dextrin, and 
laminarin. Mesogloea and Ascophyllum are similar to Fucus 
in failing to show the presence of carbohydrases. Within the 
groups there is little difference in the rate of carbohydrase 
action. This is especially true in the ‘‘greens.’’ Of the 
‘‘reds,’’? Agardhiella is a little more active than the other 
forms investigated, while Ceramium is slightly the slowest. 
Bartholemew (714), in the work already referred to, also 
found that Ceramium was less active than the other ‘‘reds”’ 
with which he worked. 
The various polysaccharides, with two exceptions, prove 
favorable as substrates for the various algae in the same 
order, viz., starch, dextrin, laminarin, and glycogen. The 
carbohydrases of Ceramwm act more rapidly upon dextrin 
than upon starch and this is also true of Laminaria, although 
