708 
T ho day. — On the Effect of Chloroform on 
The rate of respiration before treatment with chloroform was low 
owing to starvation ; the values given in the diagram are, however, rather 
too low, as they represent the average for nineteen hours. 
As in Experiment VIII there was an immediate acceleration of the 
0 2 intake, and at the same time a very unmistakable increase in the C 0 2 
output. The latter fell off, however, to a very low rate by the fourth hour, 
the 0 2 intake falling meanwhile to near its previous level. Compared with 
the low C 0 2 output before chloroform, the relatively great increase after 
chloroform suggests comparison with the experiments with starved leaves 
of Cherry Laurel in which relatively great and persistent stimulation was 
shown. 
After five hours the dose was repeated, and the results indicate a 
repetition on a small scale of the effects produced by the first dose. This 
may mean that cells hitherto but little affected were by the second dose 
strongly affected. 
It is probable that only the outer cells are effectively exposed to the 
action of chloroform vapour unless its concentration is much greater, so 
that while the outer cells are killed, the inner remain alive. This would 
explain the fact that the leaves remained, as a whole, turgid. Microscopic 
examination of the distribution of the brown coloration supports this inter- 
pretation, as at first only the outermost layers of cells are affected. 
On the other hand, repeated stimulation of a given cell is possible 
(cf. Expt. XII, with Tropaeolum , on p. 71 1), though it is uncertain whether 
the oxidation of tannin, once begun, can be further accelerated by exposing 
the cell a second time to chloroform. 
Experiment X. August 19, 1910. Dose 0-3 c.c. for five minutes. 
Temperature 18*7-1 9*2° C. Eight leaves freshly 
gathered, weighing 9*2 grammes. 
In this experiment a greater initial maximum 
rate of 0 2 intake (as in Experiment VIII) would 
have been revealed if a sample for analysis 
had been taken earlier than an hour after the 
leaves were enclosed. The total amount of 
oxygen absorbed was much greater than in 
Experiment VIII, where disorganization was 
initiated by treatment with a smaller dose of 
chloroform. 
Experiment XI. August 27, 1910. Dose, 
i-o c.c. for five minutes. Temperature, 16-17 0 C. 
Leaves freshly gathered. 
The first sample was taken after the leaves 
seventeen minutes, and two others after further 
2 4 6 8 
HOURS 
Fig. 11. 
had been enclosed for 
