1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 785 
were selected that were ‘‘clean.’’ This was an important pre- 
caution, since many adhering organisms have been found to 
be quite active enzymatically, and the presence of even a few 
might well lead to serious errors in the final results. The fol- 
lowing forms lent themselves most readily to the work:! 
Chlorophyceae 
Ulva lactuca (l.) Le Jolis 
Enteromorpha intestinalis (L.) Link 
Phaeophyceae 
Laminaria Agardhu Kjellm. 
Ascophyllum nodosum (.) Le Jolis 
Mesogloea dwaricata (Ag.) Kutz 
Rhodophyceae 
Ceramium rubrum (Huds.) Ag. 
Agardiuella tenera (J. Ag.) Schmitz 
Rhodymenia palmata (L.) Grev. 
Chondrus crispus (l.) Stack. 
Preparation of algal material.—In addition to the question 
of cleanliness, great care was taken to select only plants that 
were in a young, vigorously growing condition. These were 
brought into the laboratory, placed in large aquarium jars 
containing salt water, picked over, and all detectable foreign 
matter removed. A thorough washing in running salt water 
for two hours was then given, after which, with the exception 
of one or two forms that rapidly gelatinized, the plants were 
placed in running fresh water for 10 or 15 minutes. This 
fresh water treatment was very efficacious in causing small 
snails and other minute marine organisms to loosen their hold. 
The plants so washed were either crushed and used at once 
with the substrate for enzyme action, or they were dried for 
future use. In either case, two general ways of using the ma- 
*With the exception of Laminaria Agardhii and Agardhiella tenera, these 
binomials conform to the nomenclature as given by Farlow (Marine algae of 
New England, pp. 1-210. pl. 1-14. 1881); these two forms are as given by De 
Toni (Sylloge Algarum 3: p. 349. 1895) and Engler and Prantl (Nat. Pflanzenfam. 
17371. 1896), respectively. 
