1915] 
DAVIS—ENZYME ACTION IN MARINE ALGAE 823 
‘‘B’’ would be almost negligible were the findings not so con- 
sistent. There is a definiteness about the increase over the 
checks that can hardly be ignored. In order to get further 
evidence on this point, however, another series (table xvir) 
was set up, using urea and asparagin in 1 per cent concentra- 
tions as substrates. The flasks were maintained at a tempera- 
ture of 35°C. for 30 days. 
TABLE XVII 
THE ACTION OF DEHYDRATED CHLAMYDOMONAS CELLS UPON ASPARAGIN 
AND UREA 
Weight Nitrogen as NH; split 
Substrate algal off in 30 days Net nitrogen 
powder mgms. mgms. 
ONC AIMS yr Awe aS 220 
Asparagin .5 grams ‘‘B”’ 3.10 2.20 
Soe COR Cee 65 die he hoes eRe RTE 
.5 grams ‘‘A”’ 1.45 5 lle) 
Urea -o grams b: 3.70 2.47 
Bp sais Car aheceeereth aide .98 Bee tare tors 
Water 25 grams AY ESO wo MPMI eta cs ewes ayer 
.5 grams “B”’ SL se TE CR ae eae ea re 
In this, as in table xvi, the evidence goes to show that al- 
though the desamidization is practically negligible where the 
alga is grown with (NH3)2SOu, as a source of nitrogen, it is 
definite where the nitrogen is supplied in the amino and amido 
form. The actual splitting is small in any case. 
On the basis of the above, we can simply reason by analogy, 
and yet this analogy points to the fact that the probable 
reason for the failure to demonstrate amidase in Ulva lies 
in the failure to form that enzyme. This in turn would indi- 
cate that the great growth of Ulva in sewage-contaminated 
waters is probably due to the abundance of desamidizing bac- 
teria which those waters maintain—bacteria which break 
down the protein molecule with the ultimate setting free of 
NH3. Nitrogen, as such, becomes directly available to the 
plant. 
NUCLEASES 
The presence of nucleases in the algae has already been 
reported by Teodoresco (712), but since he investigated only 
