[Vou. 2 
802 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
The action of the potato extract upon starch was about two 
and one-half times that of Ulva, and its action on dextrin 
about twice in all of the determinations made. For some un- 
known reason the hydrolysis of dextrin by the diastase from 
Ulva ceased after the twenty-eighth day. 
TABLE X 
A COMPARISON OF THE DIASTATIC ACTIVITY OF ULVA WITH THAT OF POTATO 
LEAF TISSUE 
Sugar as glucose in 5 cc. 
Substrate |= = EEE 
50 ce. 14 days 21 days 28 days 35 days 42 days 
starch. .....|/ 8.7)|) 18/1) | 976)" 2623) 1178) 2850) 11229) | S33E Sassi Solo 
Dextrins 7. |/ 10553] 617-3 pds 250 Ae Sie ie On ede) | SO Sam | lide ne el 
ACTION OF VARIOUS ALGAL EXTRACTS UPON THE CARBOHYDRATE 
CONSTITUENTS OF AGAR-AGAR, AND OF VARIOUS GUMS, 
AS WELL AS EXPERIMENTS UPON THE AUTOLYSIS 
OF ALGAL SLIME 
Because of the large amounts of carbohydrate-containing 
slime formed by many algae, and because of the rdle this 
might play as a reserve product, it was deemed advisable to 
try out the various algae for enzymes capable of hydrolysing 
such complex carbohydrates to assimilable sugars. It was 
assumed on the basis of the work done by Konig and Bettels 
(’05) and others, that such hydrolytic products would be re- 
ducing sugars, in all probability galactoses and pentoses. 
A series was set up with each of the several algae, using 
50 ec. of .25 per cent agar as a substrate and varying amounts 
of a ‘‘diffusion-extract’’ from fresh tissue. The agar sub- 
strate was slightly viscous in the cold, but when kept at a 
temperature of 40°C., the optimum temperature for diastase, 
this was not noticeable. Toluene was used as an antiseptic. 
The flasks were shaken at regular intervals during a 30-day 
period and at the end of that time aliquot portions were re- 
moved and tested for reducing sugars. There was no reduc- 
tion in any case. 
As a parallel series, thin strips of agar were placed in test- 
tubes and 20 ce. of ‘‘diffusion-extract’’ added. Toluene was 
used as an antiseptic and the tubes kept at a temperature of 
40°C. for two months. At the end of that time no hydrolytic 
