xu,c,2 Brown and Heise: Carbon Dioxide Assimilation 89 
eine angenaherte Proportionalitaét zwischen Lichtstairke und der ausges- 
chiedenen Sauerstoffmenge durch die Athmung in 4hnlichem Sinne besei- 
tigt werden. 
One of the most widely quoted researches on photosynthesis 
is that of Pantanelli,(16) who also worked on Elodea with a 
bubble-counting method. 
Pantanelli’s results on this subject are perhaps best expressed 
in his figure a, obtained with a carbon dioxide concentration of 
1 to 15 volume per cent. We have shown in Table III all the 
readings given by him in curve a for assimilation velocities with 
different light intensities up to full sunlight. In order to make 
Pantanelli’s results comparable with those of other workers, 
we have reduced his readings from the number of seconds re- 
quired for the evolution of ten bubbles to the number of bubbles 
evolved in ten seconds. 
TABLE III.—Carbon dioxide assimilation and light intensity (Pantanelli 
on Elodea). 
[Curve (a) 1-15 volume per cent CO;.] 
pon nies ror spa Initial value. After ten minutes exposure. 
ke > on ee rf UJ Smal 
5. | #2 | #2se| =, | 28 | 625% 
Series ae | 3 | £32) ge | 25 | £252 
Frac- . 3a ” =O 2 53 £423 
os eaevan es | oe ae ae ae iy ge 
=i i=] 
oo ” oo od 
e" | 5 | e885) 2° | 5s | G8 i! 
B Ana ~ 4a = 
‘Seconds Seconds, 
ds} 0.028 33.2 3.05 1.09 35.8 2.83); LOL 
ds | 0,040 21.0 4.76 1.40 22.0 Ais oki 
ree ds | 0.066 15.0 6.66 0.71 16.0 6.25| 0.68 
- eas #| 0.111 12.3 8.18 0.33 13.8 7.60} 0.30 
+] 0.250 9.67} 10.4? we, Oto’ 
+] 1.000 7.7) 13.0 0.08 85) 118 0.01 
+ | 0.028 85.3 2.83 1.01 33.2 3.05] 1.09 
' de | 0.040 26.0 3.85 0.88 24.7 4.05| 0.82 
D 45 | ds | 0.066 19.3 6.2 0.50 18.0 5.55) 0.56 
spe: $i 610 16.1 6.6 0.31 13.9 1.2 0.37 
| 0.250 8.5| 118 Pg ERO Se EES GARE 
+] 1.000 7.07) 143 cal : ee 
As in Reinke’s work,(18) the first augmentation of the rate 
of bubble emission is in some cases proportionately greater than 
that of light. Again the results show not a direct proportion- 
ality between assimilation and light intensity, but a progres- 
sively smaller relative increase in assimilation with increasing 
illumination. 
147918 ——2 
