1084 
Irving.—The Effect of Chloroform 
to turn colour and set up irreversible changes. With o-i c.c. of chloroform 
alone—type B—could there be perfect recovery from the dose. 
In this section of experiments no smaller dose was tried, but in the 
next section we shall find that there is yet another type of reaction, 
type A, characteristic of still smaller doses. In this case the initial 
augmentation of the respiration does not fade away, but is maintained. 
This result is however not really comparable with the others, as here the 
dosing with chloroform is continuous. 
PART I. SECTION II. 
The Effect of Continuous Treatment with Chloroform 
upon Respiration. 
As the exact concentration of chloroform in the chamber is not known 
at any time with the procedure of Section I, this work was followed up 
with experiments in an air-current continuously 
charged with a constant amount of chloroform. 
To control the supply of chloroform a piece 
of apparatus was constructed by which different 
concentrations could be maintained. It took 
the form of a fine graduated pipette very tightly 
packed at its lower end with powdered chalk, 
through which the chloroform in the pipette 
percolated. This pipette was inserted into the 
middle arm of an anchor-shaped tube. See 
Fig. 8. 
The stream of C 0 2 -free air entered this tube 
at A and passed along by B , taking up as vapour 
the chloroform that percolated through the 
chalk. It then passed out at C laden with the 
| j vapour. By taking readings of the fall of the 
H ^ upper surface of chloroform across the gradua¬ 
tions of the pipette, the quantity of chloroform 
passing through the chalk plug into the air- 
current could be found. 1 The rate at which 
the chloroform passed through the chalk core 
depended upon its closeness and depth. A set 
of pipettes was prepared which gave a fairly wide 
range of filtration-rates, and to obtain intermediate rates, air-pressure 
m 
Fig. 8 . 
1 A control pipette of chloroform, with its lower end sealed, was placed in a similar position, 
and readings taken to find the correction for evaporation at the top. This was found to be so 
small that for most experiments it could be neglected. 
