72 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
needle of a hypodermic injection syringe. In the later experiments the quantities of 
chloroform have been measured by weight. The transference of the chloroform 
solutions from vessel to vessel under agitation in air we have endeavoured, as 
much as possible, to avoid. Also any unnecessary exposure of the vapour to india- 
rubber. The tubing leading from B (Fig. i) to the tap i (Fig. i) was composed, as 
far as possible, of glass ; the cork of flask B was, however, of india-rubber. The 
oxygen gas introduced into flask B for expelling its fluid was in the later experiments 
led on its way to B through i layer of chloroform solution (in D, fig. i) of the same 
dilution as that to be expelled 'rom the reservoir B (Fig. i). In these ways we tried 
to minimize the loss of chloroform that must to some extent occur from our prepared 
solution of it between its preparation and its actual entrance into the coronary vessels 
of the heart. 
In regard to the quantities of fluid perfused, these have in our experiments 
been large but variable. The pressure of the fluid as supplied in our experiments 
has varied little from experiment to experiment, and in each individual experiment 
hardly at all ; the pressures have throughout the series of experiments ranged from 
90 mm. Hg., in some earlier, to 1 10 mm. Hg. in some of the earlier and in all the 
later experiments. It is possible that in some cases a portion of the fluid supplied 
has passed through incompetently acting aortic valve-flaps. The head of pressure 
being what it was, this, however, can have had no influence upon the coronary 
supply, except to make the readings of the quantities perfused through the coronary 
system larger than the real quantities perfused. The effect of this possibility upon 
the readings of the dosage as expressed — as we maintain it should not be expressed — 
by the mass of CHC1, administered to the heart in a given time, is to make our 
readings possibly higher than the quantities really administered to the cardiac muscle. 
LITERATURE 
The literature concerning the effect of chloroform on the heart is very large. 
We propose to reserve dealing with it until the occasion of our fuller report. 
The perfusion of the isolated heart with fluids containing chloroform has been frequently 
practised on the isolated frog's heart. On the mammalian heart so perfused there is an isolated and 
incidental observation by Hedbom+ in this paper on the action of drugs on the mammalian heart. 
But in his single observation the chloroform was added to blood already containing chloral, and was 
administered to a heart previously dosed with coffein ; moreover, the dilution of the chloroform is not 
mentioned. At the time of our first communication to the Committee no other record than the above- 
mentioned by Hedbom had appeared. Since then, however, a preliminary communication ' On the 
action of chloroform, ether, alcohol, and acetone upon the excised mammalian heart ' 5 has been made 
by Professor Tunnicliffe and Dr. Rosenheim to the Physiological Society. 
RESULTS 
The action of CHC1, on the heart, as studied in our experiments, may be 
described briefly separately for each degree of its dilution that we have employed. 
