7io T ho day. — On the Effect of Chloroform on 
total amount of oxygen that has been absorbed per gramme is plotted 
against the time as abscissa, the data being taken from two experiments in 
which freshly gathered leaves were exposed to the vapour of o-i and 0*3 c.c. 
respectively, for ten minutes. For comparison with these a third curve is 
added, from another experiment, in which treatment with 0*05 c.c. chloro- 
form was followed by a typical stimulation effect. The broken lines 
represent the corresponding curves of total production of C 0 2 . 
The contrast between the typical stimulation curves and those resulting 
from more drastic treatment is obvious. The former show no such sharp 
change in the rate of 0 2 absorption as is shown in the curves for the other 
two experiments. In those, the later 
parts of the oxygen curves are prac- 
tically parallel, but at different levels 
corresponding to the different quan- 
tities of oxygen absorbed in the initial 
period. These quantities appear 
roughly proportional to the dose of 
chloroform received. 
While the amount of oxygen 
absorbed is at first far greater than 
in the typical stimulation curve, the 
amount of C 0 2 produced is smaller, 
and the difference increases the more 
rapidly the bigger the dose. 
With regard to the character of 
the augmentation produced by small 
doses, the respiratory quotient ap- 
peared to be less during stimulation 
than before treatment, even when 
the leaves remained fresh and green. 
The highest rate of respiration was 
observed as a rule within the first 
hour after treatment with chloroform, and a steady fall from this initial 
maximum followed. 
Experiments with Tropaeolum majus. 
Leaves of Tropaeolum majus do not darken during disorganization, and 
the plant was chosen for this reason, as contrasting with the Laurels and 
Helianthus. The symptom most readily observed is flaccidity, accompanied 
by exudation of water into the air-spaces, and from the water-pores and the 
cut end of the stalk. 
For each experiment the stalks were removed from sixteen small 
leaves, gathered usually a few minutes before use, and the laminae were 
1 2 3 .4 
HOURS AFTER CHLOROFORM 
Fig. 12. Curves showing total 0 2 absorbed 
and C0 2 produced after chloroform by leaves of 
Helianthus tuberosus in c.c. per gramme of fresh 
weight. 
