ACTION OF THE EXCISED MAMMALIAN HEART. 
217 
Rabbits a minimum persistence of 3 minutes, a maximum persistence of 36 minutes ; 
the mean of 60 observations was 11 minutes 46 seconds.* In the few observations 
which we devoted to this point we obtained durations considerably longer than the 
maximum given above. 
We obtained, for instance, from three Rabbits’ hearts the record of spontaneous beats 
during 72 minutes, 71 minutes, and 42 minutes respectively, and beats in response to 
excitation for as long a time as 1| hours post mortem (Nov. 28). On Cats we recorded 
spontaneous beats for periods of 25^ minutes (Nov. 30), 23 minutes (Dec. 2). On a Dog 
we observed them for 2 hours after excision. These periods were longer than we 
anticipated, but they were exceeded by a figure given by Rousseau in 1808, viz., 
29 hours post mortem,—contractions on a guillotined Woman,t also by figures given 
by Vulpian, 93^ hours (R. Auricle of Dog), 46^ hours (Auricles of Rat).t Brown- 
Sequard also gives some very high figures, 53 hours (Dog), 34 hours (Rabbit), 31 
hours (Guinea-pig).J 
It must be observed, however, that in most cases the heart remained in situ, that 
generally the movements observed were of the R. Aur. or of the Vena Cava, and that, 
as far as can be gathered from the description, the observations were generally of the 
fibrillation of minute portions placed under the microscope. Our observations, except 
in the case of the Dog’s heart above mentioned, were of complete ventricular contrac¬ 
tions giving characteristic records. The heart w r as removed immediately after 
decapitation and placed upon an adjustable platform with a light lever resting upon 
it, and our results are comparable with those of Czermak and Piotrowsky,* with this 
addition that we recorded the movements. 
Of fibrillation such as that spoken of by the French physiologists we took no 
account; we noticed it indeed, but did not follow it to its end. 
We are not acquainted with any such published records of the movements of the 
excised Mammalian heart, we therefore submit some examples illustrative of the usual 
mode of the decline and of its ordinary modifications at various times post mortem. 
(Vide Tracings 1, 2, 3, 4. Tables A, B.) 
1. Generally speaking, the decline is fairly regular as to force aud frequency of 
contraction ; force of contraction declines, however, more rapidly in the first moments 
after excision than at later periods (Tracing 1) ; frequency of contraction diminishes 
throughout the observation regularly at first (Tables A and B) ; at a later period the 
contractions are at long and irregular intervals (Table D). 
2. The supervention of a bigeminal character is frequenc as a regular irregularity. 
Sometimes the beat is bigeminal from the instant of excision to the end of observation, 
sometimes it is uniform at first and gradually becomes bigeminal. The bigeminal 
* ‘Wien, Akad. Sitzber.,’ vol. 25, 1857, p. 431. 
f ‘ Comptes Rendus,’ 1858, p. 3. 
X ' Journal de la Physiologie,’ vol. 1, 1858, p. 357. 
2 F 
MDCCCLXXXVII.—B. 
