19141 
SCHRAMM—GRASS-GREEN ALG AND ELEMENTARY NITROGEN 177 
was sterilized. After cooling, the liquid was inoculated with the 
desired organism (care being taken to avoid introducing any 
agar, which can readily be done if hard agar cultures are used 
from which to make the inoculation). Тһе DeVilbis atomizer 
is provided with an adjustable metal tip so that the spray may 
be directed downward. The metal tip further admits of steril- 
ization by flaming. By exercising care and keeping the hands 
moist with alcohol, comparatively few contaminations result, 
only four having appeared in a total of 320 inoculations. 
Attention should be called to the importance of inoculating 
in such а way that an approximately equal number of organisms 
are introduced and that they are uniformly distributed over the 
substratum. Unless this is done growth comparisons cannot 
be made with any considerable degree of accuracy, as differences 
may be due to localized and unequal inoculation. This is 
especially true in alge which do not form motile cells and which, 
therefore, are unable to spread rapidly over the substratum. 
GROWTH AND OBSERVATIONS 
All groups of flasks of the 1912 experiment were placed in the 
light of north windows at the ordinary room temperature and 
the cultures aérated at intervals of from three days to а week. 
The 1913 experiment was set up in duplicate, one-half being 
placed in a glass incubator kept constantly at from 29.5 to 30.5? 
C., and the other half in a similar incubator at the ordinary room 
temperature. Both series of cultures were placed directly in 
front of a north window and were aérated from time to time. 
Space will not permit the detailed tabulation of the observa- 
tions on growth. In the following tables, growth is indicated 
without reference to time. А few general statements may, 
however, serve to give some idea as to the relation of the com- 
position of the cultural medium to the time elapsing before a 
macroscopically visible growth appeared. In almost every 
case, growth was observed first on the glucose-containing medium 
and almost as soon or slightly later on the one containing sac- 
charose. It should be said, however, that а healthy growth 
was maintained on these two media, in most cases, for but а 
short time. Chlamydomonas pisiformis Dil forma minor 
Spargo is a marked exception in this respect, a splendid, healthy 
