420 
Baker . — Quantitative Experiments on 
Experiment II. July, 1912. 
Source of formaldehyde : solid paraform at room temperature. 
Amount of formaldehyde in air, about 0*09 %, or about three times as 
much potential carbon as in normal air containing 0*04 % of carbon dioxide. 
Temperature range, 21-2° to 29-8°. 
Duration , 22 days. 
Atmosphere. 
Air — C0 2 + CH 2 0 
Air — CO a 
Air + CO a 
Orig. dry weight. 
0-3865 grm. 
0-3855 » 
o*3875 » 
Final dry weight. 
0-3105 grm. 
°‘ 2 45 I „ 
0-4446 ,, 
Final /orig. weight. 
80*34 % 
63-59 % 
iH-74 % 
Notes. — A photograph of these cultures is shown in Plate XXX A. The 
effect of formaldehyde was to make the plants stouter and with somewhat 
broader cotyledons than those without carbon dioxide. The second leaves 
were developed, but to a less extent than in presence of carbon dioxide. 
In the two following experiments the concentration of formaldehyde 
in the air w r as five times as great as in Experiment II ; and yet it will be 
seen that there is only a very slight additional increase in dry weight pro- 
duced. From this it appears probable that the maximum assimilation of 
formaldehyde has been obtained. 
Experiment III. June, 1911. 
Source of formaldehyde : formalin at room temperature. 
Amount of formaldehyde in air, about 0-52 %, or more than fifteen times 
as much potential carbon as is present in normal air containing 0-04 % of 
carbon dioxide. 
Temperature range, 14 0 to 25 0 . 
Duration , 24 days. 
Atmosphere. Orig. dry weight. Final dry weight. 
Air — C0 2 + CH a O 0-4015 grm. 0*3585 grm. 
Air - C0 2 0-3985 „ 0-2590 „ 
Air + CO,, 0-3965 „ 0-4035 „ 
Final /orig. weight. 
89-3% 
65-0 % 
102-0 % 
Experiment IV. May, 1912. . 
Source of formaldehyde : formalin at room temperature. 
Temperature range, 14*5° to 20-8°. 
Duration, 26 days. 
Atmosphere. 
Air — CO a + CH 2 0 
Air — C0 2 
Air + C0 2 
Orig. dry weight. 
0*3845 grm. 
0*3885 „ 
0-3860 „ 
Final dry weight. 
0-3144 grm. 
0-2608 „ 
0*43 1 6 „ 
Final / orig. weight. 
84-37 % 
67-01 % 
in-8 % 
A fifth experiment was performed to see if a still further increase in the 
amount of formaldehyde would cause any increase in dry weight. The 
