Jan., 1921] 
WANN — FIXATION OF FREE NITROGEN 
9 
Series 5 (calcium nitrate, without glucose). The growth was very slow 
with all species, but all remained healthy. Total growth of species no. 2 
was ''fair," while for nos. i, 5, and 6 it was ''very fair." 
Series (calcium nitrate, with i percent glucose). All four species 
gSive vigorous growths on this medium, continuing healthy to the end of 
the experiment. The effect of the presence of glucose was apparent from 
the start. The growth of species no. 2 was "luxuriant" and appeared 
slightly better than the others, all of which were "very good." 
igip Experiment. — So^ far as this experiment duplicated the previous 
one, the same general type of growth resulted. The presence of glucose 
in the medium markedly stimulated the development of all species, irre- 
spective of the source of combined nitrogen. It is also true, however., 
that death of the cultures always occurred first on the media containing 
glucose. The presence of mannite apparently had no effect by way of 
increasing the rapidity or amount of growth of any of the species on any 
of the three media to which this compound was added. The amount of 
growth produced on these media appeared practically the same as produced 
by the same organism with the same source of nitrogen but without either 
glucose or mannite. 
Series 6 and y. As in the previous experiment, no fixation occurred 
where combined nitrogen was supplied in an organic form or as ammonium 
sulphate; growth observations for these media are therefore omitted. 
Series 8 (ammonium nitrate, without glucose or mannite). A slow, 
steady growth resulted, as in the previous experiment. At analysis all 
cultures were healthy. Species nos. i, 6, and 11 produced "very fair" 
growths; nos. 2 and 5, "fair." Species nos. 3 and 7 were not grown on this 
medium. 
Series 8 A (ammonium nitrate, with i percent glucose). All species 
grew very vigorously at first, but deterioration soon set in and by the end 
of one month all' cultures of nos. i and 2 were dead, after a "fair" growth, 
and species nos. 3 and 6 were rapidly waning. The cultures of no. 3 died 
after a "fair" growth. One culture of no. 6 also died, but the two others 
revived and remained healthy to the end of the experiment, giving "very 
good" growths. Species no. 11 gave a "luxuriant" growth, but at the end 
of the experiment was turning brown. Nos. 5 and 7 remained healthy 
throughout the growing period, both producing "very good" growths. 
Series 8B (ammonium nitrate, with i percent mannite). Growth on 
this medium was slow, and in general very much as in series 8. All cultures 
remained healthy at the end of the experiment. Species nos. i, 3, 6, and 
II gave "very fair" growths, the development being somewhat better 
than with species nos. 2, 5, and 7. 
Series g (calcium nitrate, without glucose or mannite). Growth was 
very slow, and strikingly like that in series 8. All cultures remained 
healthy, species no. 6 giving a "good" growth, nos. i and 11 "very fair" 
