1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 781 
Chemical composition—Greenish (’81) found agar from 
Fucus amylaceus to consist of 37.21 per cent gelose (probably 
galactan since it passed to galactose on hydrolysis) and that 
from Sphaerococcus crispus of 60 per cent of the same carbo- 
hydrate. Konig and Bettels (’05) give the carbohydrate com- 
position of agar-agar from Gelidiwm as 33 per cent galactans 
and 3.1 per cent pentosans; by hydrolysis, d-galactose and 
levulinic acid were split off. Giimther and Tollens (’90) 
found fucosan in Fucus from which the methyl-pentose, fucose, 
was split off. Galactose was also demonstrated. Sebor (’00) 
obtained galactose, glucose, and fructose from the slime of 
Chondrus crispus by acid hydrolysis. He held that the slime 
is a very complex carbohydrate of high molecular weight, 
made up chiefly of galactosan, glucosan, and fructosan. 
The cleavage products of Porphyra laciniata, as investi- 
gated by Oshima and Tollens (’01), were found to consist 
chiefly of l-galactose and mannose, but glucose, fucose, and 
other pentoses were also obtained. Miither and Tollens (’04) 
found methyl-pentosans in several of the Fucaceae. Konig 
and Bettels (’05), working on the carbohydrate hydrolytic 
products of various species of Porphyra, Gelidium, Laminaria, 
Cystophyllum, and Enteromorpha, found them to consist of 
such hexoses as galactose, dextrose, and fructose, as well as 
several pentoses, chiefly methyl-pentoses. Enteromorpha 
yielded a pentose—rhamnose. The results of Swartz (’11) 
agree with those above, namely, that for all forms studied, 
representatives of the ‘‘greens,’’ ‘‘browns,’’ and ‘‘reds,’’ 
pentosans were always present, and galactans frequently so. 
Kylin (713), by direct extraction with warm water of crushed 
Ceramium, Furcellaria, and Dumotia, obtained substances 
that gave the mucic acid test for galactose, as well as 
the phloroglucin test for pentosans. Substances giving pen- 
tosan reactions alone were isolated from the slime of Asco- 
phyllum nodosum, Fucus vesiculosus, and Laminaria sp. He 
was apparently unable to substantiate the finding of galactan 
in Fucus by Giinther and Tollens, and this negative result also 
conflicts with the statement of Swartz, who says that the 
gelatinization in the algae is due to the galactan groups. 
