1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 819 
these in neutral and slightly alkaline solution. This was 
shown in the formol titrations! and in the determination of 
the nitrogen in the amino acids split off. Albumin was slowly 
acted upon by Enteromorpha, Mesogloea, and Chondrus. The 
first and last also hydrolysed the vegetable protein, legumin, 
to a slight extent—an action that was not shared by Mesogloea. 
The action of algal powder on the proteolysis of gelatin and 
albumin in Mett’s tubes.—T wo lots of Mett’s tubes were made 
up, one containing coagulated egg-white, and the other, 15 per 
cent gelatin. In each of a series of flasks containing 50 cc. 
of distilled water, N/200 NaOH and N/200 HCl respectively, 
were placed one tube each of egg-white and gelatin. Two 
grams of the powdered tissue from each of the several forms 
under investigation were added for enzyme action and the 
usual percentage of toluene used as an antiseptic. The sev- 
eral series were kept for two months at room temperature. 
At the end of that time the albumin tubes in the alkaline solu- 
tion containing the algal powder of Ulva, Enteromorpha, 
Chondrus, and Agardhiella showed a slight digestion. The 
checks in the alkaline solution alone showed swelling. How- 
ever, although this was indicative of action, it was not definite, 
since the great length of time the protein was in contact with 
the complex constituents of the tissue may have been a factor 
in either causing a slight hydrolysis or a contraction of the 
albumin. On the other hand, Laminaria, Ascophyllum, Meso- 
gloea, and Ceramiwum caused no such action. The gelatin tubes 
showed no evidences of action even after 60 days. 
The effect of proteinases on the hardening of gelatin.—Dox 
(710) describes a method for testing the hydrolysis of gelatin 
which consists in keeping the protein in a liquid state during 
contact with the material being tested for proteolytic activity, 
then at the end of a stated period noting whether the gelatin 
congeals when placed in cold water. This method was used 
in the following way: Five cc. of 20 per cent gelatin were 
placed in each of a series of test-tubes, and 5 ce. of the standard 
1 The formaldehyde titrations, as used here, were satisfactory only in a general 
way, i. e., to show relative rather than exact differences in the amounts of amino 
acids split off. The differences brought out by the amino-nitrogen determinations 
are much more exact. 
