1094 
Irving.—The Effect of Chloroform 
The leaf weighed 2 -i grms., hnd was set up in the chamber in the 
usual way. 
Two normal respiration readings were taken in the dark and then 
chloroform was given; after which five more readings were taken, still in 
the dark. Fig. 18 shows that during this time the reaction started to be 
of the A-B type. At the end of the seventh reading the leaf was illumi¬ 
nated. No further fall in the output of C0 2 took place during the readings 
in the light. When the leaf was darkened once more, the output of C0 0 was 
still found to be keeping fairly uniform. 
From this we see that o-os c.c. of chloroform per litre of air-current, 
given continuously, abolished completely the power of assimilation. 
The green colour of the leaf here also remained unchanged throughout 
the experiment. 
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Fig. 19. 
Experiment XVII. Concentration of chloroform — 0-091 c.c. per litre 
of air-current. In this experiment simultaneous readings were taken of 
two separate leaves, one in the light (weight, 3-30 grms.), the other in the 
dark (weight, 3-31 grms.). Both were given preliminaries of 3 hours. 
After normal respiration and assimilation readings, respectively, had been 
taken, chloroform was given to both in equal concentrations. The results 
are seen in Fig. 19 . 
It will be noted that in the lighted leaf not only was all assimilation 
of C 0 2 arrested by the chloroform, but an outburst of C 0 2 , comparable 
