ds ei enc oi асы м Ж” X 
1914] 
SCHRAMM—GRASS-GREEN ALG AND ELEMENTARY NITROGEN 181 
TABLE IV 
SUMMATION TABLE OF 1912 AND 1913 EXPERIMENTS 
(Solutions numbered as in 1913 experiment.) 
Sol. 1 80]. 2 801.3 | Sol. 4 |80]. 5 | Sol. 6 |Sol.7| Sol. 8 
Organism (with-| (with | (with-| (with | (with-| (with |(with-| (with 
out | c.n.) | ош c.n.) out c.n.) out c.n.) 
c.n.) c.n.) c.n.) c.n.) 
Chlamydomonas 
pisiformis Dill 
forma im 2” ВЕ — |+ = 1++++| - +++ 
Spargo 
Chlorella sp. = MEE — T = +++ "- Bp ер 
Stichococcus bacil- 
laris Nag. е ТЕЧ! — TT - ^ = T 
Chlorococcum hu- 
micola (Näg.) = Hd = [+++ - t A 5 зи жө дік т 
Rabenh. 
Protosiphon botry- 
oides (Kütz.) = ger = qn = ЕЕ E +++ 
Klebs 
Chlorella vulgaris 
Bey. - ҒҒ = qe = T ме TE 
Kirchneriella sp. - + - + - + Е 4. 
assimilable energy-furnishing compounds like glucose, mannite, 
and saccharose are supplied; and that, therefore, these forms, 
under the conditions stated, are totally unable to fix free atmos- 
pheric nitrogen in the complete absence of combined nitrogen. 
CoNCLUSIONS 
1. In agreement with all work that has previously been done 
on the assimilation of elementary nitrogen by grass-green alge 
in pure culture, it has been found that Chlamydomonas pisiformis 
Dill forma minor Spargo, Protosiphon botryoides (Kiitz.) Klebs, 
Chlorococcum humicola (Nàg.) Rabenh., Chlorella vulgaris Bey., 
Stichococcus bacillaris Nàg., Chlorella sp., and Kirchneriella sp., 
are unable to fix free atmospherie nitrogen in the complete 
