to exert its controlling, its balancing power. And so intermittent action of the heart, as it is due to what may be considered accidental failure contracted during an intense emotional effort, or to senile failure of organic function, is traceable, I think, fairly and logically to failure of those centres of the sympathetic system which supplement the true cardiac centres in supplying contractile power.

Of the nature of the failure of the nervous centres we know as yet so little, that the best pathologist can scarcely speak with authority. Indeed, the whole subject of the morbid changes belonging to the ganglia of the sympathetic system is still imperfectly known. But from a physiological point of view, we may safely infer that each centre of the nervous system is a reservoir or receptacle of force derived, not merely from the blood with which it is fed, but also from the parts which the nerves are said, incorrectly, to supply. In these centres, molecular changes, as yet, to us, imperceptible, may be understood as inducing deficiency of retaining power, and what is commonly called nervous debility and exhaustion, so that the centres cannot persistently carry on their allotted natural function.

It will add to the truth of the theory I have put forward · respecting the seat of disease in cases of intermittent pulse, to refer to an experimental truth adduced in my original paper. At the time when that paper was written and my mind was charged with the idea of the cerebral origin of intermittent action, I conceived it would be possible to induce intermittency by temporarily destroying cerebral function. I therefore entirely destroyed brain function by freezing the hemispheres in an inferior animal, but, although by this method the most complete insensibility was induced, there was no satisfactory indication, as I then reported, of intermittent motion of the heart. I thought this result was due to the circumstance that the parts at the base of the brain had not been affected. But

I have since found that if an animal be rendered insensible by exposure of the whole cerebrum to extreme cold, there is no intermittent action: if, however in this state the animal be allowed to inhale vapour of chloroform, the intermittent action is at once set up, the ganglionic organic centres being now involved. At the same time, the ganglionic system may be influenced by some physical injuries of the cerebral surface, without implication of the voluntary nervous system: this is occasionally seen in cases of concussion.

The recent researches of Waller, Rutherford, Wood of Philadelphia, and others, on the functions of the pneumogastric, deserve, finally, a word. It has been so clearly demonstrated that irritation of the pneumogastric produces what is called "slowing" of the action of the heart, the inference seems to come naturally that intermittent action is or may be a result of such irritation. But direct observation does not support this view. When the pneumogastric in the neck is subjected. to irritation, the action of the heart is lowered, and there are induced signs of faintness, and what Waller calls asthenia. Waller has in fact induced temporary faintness in the human subject by mechanical irritation of the pneumogastric, for the purpose of aiding in the reduction of dislocation.* But from what I learn from observation on the inferior animals, the same irritation, while it produces symptoms of faintness and asthenia, does not produce the intermittent cardiac action which is now under our consideration; and, what is equally to the point, patients suffering from intermittent pulse are not necessarily subject to symptoms directly indicating irritation of the pneumogastric.

I repeat, therefore, my present conviction, as I close this section of the subject, that the seat of the nervous lesion is in the nervous centres which supply the reserve contractile power of the heart, I mean the sympathetic nervous centres that go to

Proceedings of the Royal Society, May, 1870.

LANE UBRARY, STANFOR

feed the heart, and that the change in those centres, whatever it may be physically, leads to their failure as reservoirs or condensors of force.*

* I must not allow this paper to leave my hand without acknowledging a work indifferently known, and yet full of the most suggestive and original thought. I refer to the work of Dr. Davey, of Northwoods, Bristol, on "The Ganglionic Nervous System." Dr. Davey has most clearly appreciated the functions of the organic nervous centres, and has described his views in a volume which, when the jealousies, prejudices, and ignorances, that always beset the present, concerning the present, have passed away will be discovered by some future and unbiassed scholar as a neglected classical work of the physic of the nineteenth century.

CHAPTER V.

ON THE SIGNIFICANCY AND PERSISTENCY OF INTERMITTENT

PULSE.

The Significancy of Intermittent Pulse.

In itself, when it is not present in an exaggerated degree, intermittency of the pulse is less dangerous than it seems. It does not, as might be feared, carry with it the necessary idea of sudden dissolution from heart disease, for, as I have elsewhere shown, the heart is the regulator, not the prime mover, of the circulation. The harmlessness of the symptom in its moderate development is best shown by the facts of its common occurrence after middle age, and the long duration of life in many of those who present it.

At the same time the symptom has its significance. Occurring in infancy, it is an important indication of the existence of serious nervous derangement. Occurring in adults it has the same meaning, and tells the story of commencing failure of power. Occurring suddenly after any great event, which has told upon the mind, it may be a sign of serious import. My own experience connects it as the first physical indication of derangement in three cases of disorder of mind in which suicide was attempted, in two of the cases successfully. Further, it becomes an embarrassing sign in all conditions where there is diminished condensation of force in the nervous centres, where force is either not laid up or is given out too freely.

In persons advanced in life, and in persons prematurely old, intermittency is often the herald of symptoms of nervous failure. In these examples the patient has sometimes a sin

F

gular preconception of impending danger; he is seized without reason with what I once heard a patient call "panic." These also are cases of very serious import. The symptom may again be increased until it lapses into veritable and fatal disorder, from continuance of morbid change in nervous matter.

In the large majority of patients there is an unconsciousness of the intermittency. We listen to the heart, we hear the phenomenon distinctly, and we ask the patient, at the moment, whether he is conscious of anything peculiar, and he tells you he is not. In such instances, the intermittent phenomenon does not cover more than what would be one or at most two normal periods of cardiac contraction, and there is a long interval before the return of it. But when the intermittency

covers a period equal to five normal strokes, or when it is repeated in shorter periods, several times in the minute, then the patient is painfully, often fearfully, conscious of the fact. Then breathing becomes irregular, then there is difficulty in keeping the recumbent posture, then there is sleepless agitation, terrible mental depression, a constant dread of death, sometimes with a singular longing for that event, and finally death itself, not suddenly, but by a lingering and sinking asthenia. These are true cases of what has been poetically called "broken heart."

I have seen one well-marked case, already referred to, in which it was impossible to attribute death to any other cause than intermittent cardiac action, and I do not remember any case where the symptoms, which long preceded death, were so acutely painful. The heart intermitted in this patient, ten, and even twenty times in the minute, and some intervals of hesitation were so prolonged, that sense of faintness and impending death tormented the sufferer. He feared to lie down, since that increased the evil; he feared to sleep for the same reason; and as he got weaker from pain and broken rest,