DOSAGE OF THE MAMMALIAN HEART BY CHLOROFORM 
obvious in five seconds from the admission of CHC1, fluid to the heart. The full 
effect was always reached in the second minute of administration, or sooner. The 
heart would not infrequently be beating better at end ot the fifth or tenth minute 
than at end of the first minute, e.g., Heart 28, observation 5. Even by end ot 
the third minute of administration the beat is sometimes distinctly stronger than at 
end of the second minute. 
Recovery was always rapid and complete, beginning a few seconds after 
cessation of the administration and becoming complete in two to four minutes. 
The frequency ot rate of beat remained unaffected by the exhibition ot the 
CHC1 ; solution — thus, even when the beat was reduced in excursion by 95 per cent., 
the frequency remained absolutely the same. When, as was twice the case, the heart 
was beating in groups, the phasic groups continued unaltered in period, although 
each number of the series ot contractions was reduced in the same proportion as 
were the other members. (Fig. 13). 
IX. 20 mgrms. CHC1 ? per Litre Modified Ringer's Fluid 
(CHC/ J in "002 per cent, dilution) 
This strength ot chloroform solution we have employed in the instance ot one 
heart only. The beat of the auricle was, as a mean of six observations, reduced in 
amplitude by 36 per cent. ; that of the ventricle by 33 per cent. The cessation ot 
exhibition of the drug, even when it had been perfused for five minutes continuously, 
was always followed by rapid and full recovery. The utmost (temporary) reduction 
of the auricle was 48 per cent., of the ventricle 50 per cent. ; the least reduction ot 
the auricle was 27 per cent., of the ventricle 28 per cent. The chloroform caused 
no alteration in the frequence or regularity of the rhythm of the beat. 
X. 19 mgrms. CHC1 ; per Litre Modified Ringer's Solution 
(CHCIj in -0019 percent, dilution) 
With this strength of solution we have observations on one heart only, a dog's 
heart. The beat of the auricle alone was recorded. The weakening of the beat, as 
estimated by the reduction of the excursion of the recording lever, amounted to 69 
per cent. The full effect of the drug was obtained in about seventy-five seconds 
from commencement of the administration. When the administration was prolonged, 
e.g., to ten minutes, the heart was rather less affected toward the end of the dose than 
at the beginning of the dose. 
XI. 15 mgrms. CHC1 3 per Litre Modified Ringer's Solution 
(C//C/j in "0015 per cent, dilution) 
(Fig. 9) 
The auricular beat was always obviously weakened. The degree of weaken- 
ing, as indicated by reduction of the amplitude ot the excursion of the recording 
