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 ('14), 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 Ceramium act more rapidly upon dextrin 

 than upon starch and this is also true of Laminaria, although 



