[Vou. 2 
820 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
““diffusion-extract,’’ described under ‘‘carbohydrases,’’ used 
for action. The contents of the tubes were made neutral, 
and acid and alkaline to N/200, as was done in the other pro- 
teolytic experiments. Five drops of chloroform-thymol were 
added as an antiseptic. Checks were set up containing the 
gelatin together with 5 ce. of boiled ‘‘diffusion-extract.’’ The 
tubes were placed in an incubator at 35°C. for a week, at which 
time they were removed and cooled in running water. All 
tubes hardened in a short time, showing that no hydrolysis 
had taken place. 
General results for experiments on proteolysis——The pro- 
teolytic activity, although slow, as was the case with the 
other enzymes investigated, is definite enough to warrant 
the statement that proteinases and peptases are very gen- 
erally present in the algae. When present, such enzymes 
act best under neutral and alkaline conditions. This last 
finding is interesting in the light of the existing differ- 
ences of opinion regarding the relative value of acid and 
alkaline substrates for vegetable proteinases. It will be re- 
called that Vines (’97) found that acidity favored the pro- 
teinase contained in the leaf pitchers of Nepenthes, and in a 
later paper, he states that peptase (hydrolysing albumoses 
and peptones to amino acids) always act best under faintly 
acid conditions. Emmerling (’02), on the other hand, demon- 
strated that the papain of Carica papaya acted more rapidly 
when the substrate was alkaline. Euler (’12) states in a 
general way that peptases require a neutral or faintly alka- 
line substrate, and proteinases (tryptases) an acid one. 
Of the proteins employed, solutions of casein and peptone 
prove the most favorable substrates. Albumin in solution is 
acted upon slowly, but when employed in the form of Mett’s 
tubes, doubt exists regarding its digestion. Legumin appears 
to be slowly hydrolysed by Enteromorpha and Chondrus, but 
not by Mesogloea. Gelatin, either in the liquid state or in 
the form of Mett’s tubes, is not attacked. As groups, the 
‘‘reds’’? appear more active in proteolysis than do the 
‘‘oreens,’’ while, as was true for carbohydrases, the ‘‘browns’’ 
show the least activity. 
