70 6 Thoday . — the Effect of Chloroform on 
I and II with Cherry Laurel, which suggests that all the effects take place, 
or show themselves, much more rapidly in Helianthns , where stomata are 
present on both sides of the leaves and exchange of gases is normally rapid. 
A determination made after twenty-three hours showed a further slight fall in 
the rates ; the C 0 2 output still bore a smaller proportion to the 0 2 intake 
than before chloroform. The leaves remained quite green to the end. 
Experiment VII. July 7, 1911. Dose, o*i c.c. for five minutes. Tem- 
perature, 22*2-24*7° C. Five leaves weighing 7*5 grammes. 
The leaves used had been gathered the day before and left in the dark 
for twenty hours. Immediately after treatment with chloroform they were 
Fig. 8. 
still turgid and green. After five and a half hours the leaf-chamber was 
opened and signs of a small amount of local disorganization were then 
visible. Twenty-two hours after chloroform respiration had fallen approxi- 
mately to its original level, but disorganization was slowly spreading. 
Stimulation was here relatively greater than in the previous experi- 
ment, in which the dose was only half as big, though applied for double the 
time. The absorption of oxygen was again affected more than the produc- 
tion of C 0 2 , and the respiratory quotient remained at the lower level. 
In the following experiments disorganization had already begun when 
the leaves were enclosed in the respiration chamber. 
Experiment VIII. August 25, 1910. Dose, o*i c.c. for ten minutes. 
Temperature, 17*4-1 8-2° C. Eight leaves freshly gathered, weighing 12*8 
grammes. 
When removed from the chloroforming vessel, the leaves had already- 
begun to show signs of disorganization over the greater part of their surface. 
The first sample of air for analysis after chloroform was taken when the 
leaves had been enclosed for a quarter of an hour. Analysis gave as the 
composition of this sample o*6 % C 0 2 and 19*1% 0 2 . Thus in this short 
time the leaves had absorbed more than 2 cubic centimetres of oxygen 
