PHENOMENA IN THE CIRCULATORY SYSTEM AFTER DEATH. 113 



actually increase the rapidity of the circulation. Hering has settled these questions ex- 

 perimentally. His observations were made on horses, by increasing the frequency of 

 the pulse, on the one hand, physiologically, by exercise, and on the other hand, patho- 

 logically, by inducing inflammatory action. He found, in the first instance, that, in a 

 horse, with the heart beating at the rate of thirty-six per minute, with eight respiratory 

 acts, ferrocyauide of potassium injected into the jugular appeared in the vessel on the 

 opposite side after an interval of from twenty to twenty-five seconds. By exercise, the 

 number of pulsations was raised to one hundred per minute, and the rapidity of the cir- 

 culation was from fifteen to twenty seconds. The observations were made with an 

 interval of twenty-four hours. The same results were obtained in other experiments. 

 Here there is a considerable increase in the rapidity of the circulation following a physio- 

 logical increase in the number of beats of the heart; but the value of each beat is materi- 

 ally diminished; otherwise, the rapidity of the current would be increased about three 

 times, as the pulse became three times as frequent. In its tranquil action, with the pulse 

 at thirty-six, the heart contracted thirteen times during one circuit of blood ; while it 

 required twenty-nine pulsations to send the blood over the same course, after exercise, 

 with the pulse at one hundred; showing a diminution in the value of the ventricular sys- 

 tole of more than one-half. In animals suffering under inflammatory fever, either spon- 

 taneous or produced by irritants, the same observer found a diminution in the rapidity 

 of the circulation, accompanying acceleration of the pulse. In one observation, inflam- 

 mation was produced in the horse by the injection of amn\onia into the pericardium. At 

 the commencement of the experiment, the pulse was from seventy-two to eighty-four 

 per minute, and the duration of the circulation was about twenty-five seconds. The next 

 day, with the pulse at ninety, the circulation was accomplished in from thirty-five to 

 forty seconds; and the day following, with the pulse at one hundred, the rapidity of the 

 circulation was diminished to from forty to forty-five seconds. 



If we be justified in applying the above-mentioned observations to the human subject 

 (and there is no reason why this should not be done), it is shown that, when the pulse is 

 accelerated in disease, the value of the contractions of the heart, as represented by the 

 quantity of blood discharged, bears an inverse ratio to their number and is so much 

 diminished as absolutely to produce a current of less rapidity than normal. 



With regard to the relations between the rapidity of the heart's action and the gen- 

 eral rapidity of the circulation, the following conclusions may be given as the results of 

 experimental inquiry: 



1. In physiological increase in the number of beats of the heart, as the result of exer- 

 cise, for example, the general circulation is somewhat increased in rapidity, though not 

 in proportion to the increase in the pulse. 



2. In pathological increase of the heart's action, as in febrile movement, the rapidity 

 of the general circulation is generally diminished, it may be, to a very great extent. 



3. Whenever the number of beats of the heart is considerably increased from any 

 cause, the quantity of blood discharged at each ventricular systole is very much dimin- 

 ished, either from lack of complete distention or from imperfect emptying of the cavities. 



Phenomena in the Circulatory System after Death. We do not believe that any one 

 has proven the existence of a force in the capillaries or the tissues (capillary power) which 

 materially assists the circulation during life or produces any movement immediately after 

 death ; and we shall not, therefore, discuss the extraordinary post-mortem phenomena 

 of circulation, particularly those which have been observed by Dr. Dowler in subjects 

 dead of yellow fever. But nearly every autopsy shows that, after death, the blood does 

 not remain equally distributed in the arteries, capillaries, and veins. Influenced by 

 gravitation, it accumulates in and discolors the most dependent parts of the body. The 

 arteries' are always found empty, and all the blood in the body accumulates in the venous 

 system and capillaries ; a fact which was observed by the ancients and gave rise to the 

 8 



