78 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
lever, varied between 10 per cent, and 50 per cent. The average weakening in seven 
observations on three hearts was 30*5 per cent. Recovery was always rapid, be- 
ginning a few seconds after cessation of the administration and reaching completion 
in from ninety seconds to four minutes. 
The ventricular beat was likewise also obviously weakened. The reduction 
of the beat varied from 26 per cent, to 49 per cent. ; it averaged in three hearts 38 
per cent. The weakening began within ten seconds of commencement of administra- 
tion, and obtained full effect in seventy seconds. It tended to diminish as time went 
on, being less marked at end of the seventh minute than at end of the second 
minute of administration. 
In Heart 30 the effect of this strength of CHC1 ? solution was compared with 
that of a solution of twice the concentration on the same heart, the weaker solution 
being administered first. The weaker solution reduced the auricle beat by 30*3 per 
cent, (mean of three observations), the ventricle beat by 26 per cent. ; the stronger 
solution reduced the auricle beat by 85*2 per cent, (mean of three observations). 
Recovery began about as soon after withdrawal of the stronger as after withdrawal of 
the weaker solution ; but the completion of the recovery took longer for the former. 
The frequency of rate of beat was not affected by the exhibition of the CHC1, 
solution. 
XII. 10 mgrms. CHC1, per Litre Modified Ringer's Solution 
( CHCl } in - ooi per cent, dilution) ( 1 in 150,000 by volume ) 
(Fig. 10) 
With this strength of solution, only a small reduction of the activity of either 
auricle or ventricle was observed. We have employed it in the case of two hearts. 
In ten observations on these two hearts the average reduction in amplitude of the 
excursion of the lever recording the ventricular beat was 21*7 per cent. ; the aver- 
age reduction of the auricular beat was more, but in these two hearts the auricular 
record was not very satisfactory. There was usually a very slight increase in amplitude 
of the ventricular beat, just at outset of the exhibition of the drug. Recovery was full, 
but not obviously more rapid than after stronger solution. There was no alteration 
in the frequence or regularity of the cardiac rhythm. An illustration of the effect of 
this strength of chloroform solution is given in Fig. 10. 
With weaker solutions of chloroform than this last we have not worked. 
Perfusions with Locke's Fluid 
We have made comparatively few perfusions with Locke's fluid. The 
observations are at present insufficient to generalize upon. The fluid maintains the 
heart better than does Ringer's fluid, and as a vehicle for chloroform amounts from 
the physico-chemical point of view to practically the same thing as the ' Ringer.' 
