[VoL. 2 
780 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
content ranging from .20 per cent in Enteromorpha to .98 
per cent in Porphyra. 
RELATION OF THE ALGAE TO NITROGEN 
Some of the recent work on pure culture methods with 
fresh-water algae, such as that of Beyerinck (’90), Charpen- 
tier (’03, ’03*), Chick (’03), Artari (’13), Spargo (’13), and 
Schramm (’14) have conclusively proved that these forms can 
utilize organic nitrogen. Furthermore, the work of Letts and 
Hawthorne (711), and Foster (’14) point to the fact that the 
marine forms may have this capacity as well. Letts and Haw- 
thorne and also Letts and Richards (’11) showed that Ulva 
latissuma grew better in sewage-contaminated sea-water than 
in water from the open sea. Foster placed strips of Ulva 
lactuca in normal and artificial sea-water, containing in addi- 
tion compounds of nitrogen in varying concentrations. When 
urea or ammonium sulphate was added to either solution an 
accelerated growth took place. 
The current conception concerning the assimilation of 
organic nitrogen by the animal organism is that the protein 
and amino acid molecule must be completely desamidized be- 
fore the building-up process can begin. In the absence of 
definite information to the contrary, we can conceive of a par- 
allel situation existing in the plant. The question at once 
arises in regard to the algae, whether this be due to the agency 
of amidases formed by the tissue, or to the activity of desamid- 
izing bacteria, the presence of which Brandt (’99), Gran (’02), 
Baur (’02), Reinke (’03), Benecke and Keutner (’03), and 
others have shown to exist abundantly in harbor waters. 
Neither Letts and Hawthorne nor Foster worked with pure 
cultures, and these bacteria may have been the agency in their 
experiments to render the amino-nitrogen assimilable, 
CARBOHYDRATES AND CARBOHYDRATE CLEAVAGE PRODUCTS OF 
ALGAL SLIME 
Besides the carbohydrates that may be directly assimilable, 
we find those whose function in metabolism is more or less 
disputed. The so-called algal slime is made up chiefly of such 
products. 
