1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 813 
plainable on the ground that the casein gave rise to a slight 
acidity. 
Specificity of action might explain the failure to obtain 
action on most of the esters. Euler (’12) differentiates the 
lipases into true lipases and esterases, the former acting on 
neutral fats particularly, the latter on the methyl and ethyl 
esters of the lower fatty acids. Even in this latter restricted 
field, great specificity may be shown. Reed (’12) found that 
ethyl acetate was quite rapidly acted upon by an esterase 
isolated from Glomerella rufomaculans, while ethyl butyrate 
was only slightly hydrolysed. 
THE PROTEINASES 
The proteolytic activity of the various algae was tested on 
albumin, casein, legumin, peptone, gelatin, and in certain 
cases, on proteins isolated from the algal tissue—most of 
these under acid, alkaline, and neutral conditions. The first 
four were made up in 1 per cent concentrations. Albumin 
and peptone went into solution quite readily; legumin and 
casein, being insoluble in water, were either weighed out 
directly, or dissolved in N/10 NaOH. ‘The albumin and 
gelatin were also tested in the form of Mett’s tubes, and the 
gelatin alone in test-tubes where it was held at a temperature 
high enough to keep it in a liquid state while in contact with 
the algal powder. In all cases, algal tissue was used directly, 
either fresh crushed, or dry powdered—usually 2 grams of 
the powder or 5 grams of the fresh tissue to each 50 cc. of 
substrate. 
Determination of hydrolysis——Proteolytic action was de- 
termined in several ways, each acting as a check on the others. 
The biuret test was used for the demonstration of tryptic 
action, the proteins being precipitated by (NH4)eSO4 in 
saturated solution and the test applied in the usual way. The 
tryptophane test was employed for ereptic action and this 
also furnished a check on the action of trypsin. In this, 1 ce. 
of the protein solution was placed in a small evaporating dish, 
a drop of glacial acetic acid added, and then a few drops of 
strong chlorine water. The hydrolysis to the amino acid stage 
