Jan., 192 1] WANN — FIXATION OF FREE NITROGEN 1 7 
5A. Same medium, with i percent glucose 
— 
Check (Loss) 
Ster. 
22.603 
148.50 
/ 15-221 \ 
1 1 6.903 
Check (Loss) 
Ster. 
18.360 
Id? zLO 
\ 12 d'^6 / 
I 
Chlorella vulgaris 
+ + + + + 
35-274 
147.05 
23.988 ' 
24.430 
+ 7.527 
45.1 
I 
Beyr. 
+ + + + + 
36.572 
147-05 
24.871 ^ 
2 
Stichococcus sp. 
++++++ 
36.029 
147-25 
24.468 
, 23.604 
+ 6.701 
39-6 
2 
Chlorella (?) sp. 
++++++ 
33-519 
147.40 
22.740 ^ 
5 
+ + + + + 
35-327 
147.80 
24.402 
1^ 24.402 
+7-499 
44-3 
5 
+ + + + + 
Lost 
147.90 
6 
Scenedesmus (?) sp. 
+ + + + + 
35-502 
148.25 
23.947 
6 
+ + + + 
34.607 
148.80 
23-257 
^23.956 
+7-053 
41.7 
6 
+ + + + 
36.590 
148.35 
24.665 
Average all cul- 
tures 
24.098 
+7.195 
42.5 
Tables 6 and 6A. Results of analyses of mineral nutrient agar cultures of green algae. 
Experiment of 1919. Growth period, 165 days. Nitrogen source, urea 
6. Medium without glucose 
No. 
Culture 
Species 
Growth 
Total Mg. 
N Found 
Wt. of 
Medium, 
Grams 
Mg. N per 
100 Gr. Average 
Medium 
Mg, Loss 
or Gain, 
100 Gr. 
Check 
Ster. 
25.212 
148.05 
17.029 
Check 
Ster. 
26.315 
148.30 
17-744 
^ 17.465 
Check 
Ster. 
26.161 
148.45 
17.623 
I 
Chlorella vulgaris 
+ + + 
24.807 
148.15 
16.745 
I 
Beyr. 
+ + + 
24.779 
148.15 
16.726 
> 16.696 
-0.769 
I 
+ + + 
24-583 
147-95 
16.616 
2 
Stichococcus sp. 
24.667 
148.05 
16.661 ] 
2 
24.988 
148.05 
16.878 
> 16.714 
-0.715 
2 
24.580 
148.05 
16.603 , 
5 
Chlorella (?) sp. 
25.212 
148.05 
17.029 
5 
24.779 
148.15 
16.726 
> 16.737 
-0.728 
5 
24.388 
148.20 
16.456 ^ 
6 
Scenedesmus (?) sp. 
+ + 
24.480 
148.15 
16.524 
6 
+ + 
24.960 
148.25 
16.836 
^ 16.831 
-0.634 
6 
+ + 
25-407 
148.30 
17.132 . 
II 
Chlorella (?) sp. 
+ + 
25-687 
148.20 
17.333 
II 
+ + 
25-533 
148.30 
17.217 
y 17.199 
— 0.266 
II 
+ + 
25.282 
148.30 
17.048 J 
Average all cul- 
tures 
16.835 
-0.630 
t Because of the use of some old Jena flasks in completing Series 5 and 5A, a number of 
determinations of checks and cultures were lost. Accordingly, the highest complete check 
determination is taken for the nitrogen content of the media of these two series. 
