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the symptom to have come, by descent, from their parents. It is fair, however, to notice that one of these two patients was subjected to considerable fatigue, involving disturbance of rest at the time he became aware of the intermittence, that the action of his heart was feeble, and that there was a constant sense of weariness, although his body was well formed and nourished, and his general appearance healthy.
In this case the intermittent action was sharp and abrupt, and there was no double second sound, the interruption giving rise to a modification of heart sounds like this ;—from the natural Lūb dúp 0, to O dúp 0, followed by the natural Lūb dúp 0. Under rest there was great improvement in both these cases, and I believe the patients are still living and pursuing their ordinary occupations, with little inconvenience; excess of exertion requires, however, to be strictly avoided by them.
Congenital Intermittent Pulse.
In one instance I noticed an intermittent pulse in an infant on the day of his birth, and it continued in him in the most marked degree for five years. It then gradually passed away. A medical friend once also brought me one of his children, a boy five years old, who had the symptom in an intense form, so that the parent was seriously alarmed; but the boy himself was quite unconscious of any suffering or ailment. In this case the symptom has disappeared, and the boy, now nearly fourteen years old, is in good health.
Intermittent Pulse from Old Age.
In old age intermittent action of the heart is exceedingly
It is very rare indeed to find a person above seventy who does not present the symptom. At the same time it is not necessarily connected with length of days, for I once had the opportunity of examining the pulse and the heart of a woman, in the workhouse at Birmingham, who had attained the remarkable age of one hundred and three years, and in her case the sounds of the heart were as perfect as they could be in respect both to tune and time. The action of the heart was feeble, the strokes fifty-eight in the minute, but there was perfect natural action and natural accord between the respiratory sounds and those of the heart. This woman could always eat, drink, and sleep well, and it is singular that she was a desotee to tobacco. She smoked from the time she was a young woman, and no greater punishment could be inflicted on her than the depriving her of her pipe. In the old, when intermittent action of the heart comes on, it appears only to indicate a natural failure of power, and especially of power in the digestive apparatus and the other systems of simple organic or vegetative life. When aged people thus affected are dying from prolonged senile sleep, it is often to be observed that the intermission of the action of the heart extends over periods of several seconds, so that the observer wonders how life can be sustained with such loss of motion.
General Note on cases of Intermittent Pulse.
In the illustrative cases given above I have, I think, briefly but fairly indicated the great classes of cases in which the phenomenon is developed. From what I have learned it does not occur to me that intermittent pulse is peculiar to either sex, neither does it occur to me that any period of life is exempted from it; but it must be admitted, at the same time, that the symptom is most frequently seen in persons of advanced life, and that in very aged people the absence of it is the exception rather than the rule. It is by no means unfrequent in persons of middle age, and it is as common in those who are prematurely as in those who are veritably old. It is least frequent between the ages of ten and thirty years.
Intermittent Pulse in Inferior Animals.
I noticed in my original essay on intermittent pulse that the symptom was sometimes met with in dogs. A neighbour of mine had an old Italian greyhound that presented the phenomenon in the most singularly distinct form. I also had a dog that presented the symptom ; this animal was not young, but hearty, and disposed to fat and somnolency. I have since met with several cases in dogs, but not in any other animal. It would be a very interesting and at the same time useful inquiry, in comparative pathology, to determine if the symptom be present in other animals, in horses specially, and I should be obliged if any medical man or veterinary surgeon who might observe the symptom in the lower animals would either favour me with the facts for publication or publish them independently.
ORGANIC CAUSE OF INTERMITTENT PULSE RESUMED.
The clinical history of intermittent pulse clearly in the mind, it will be advantagous to resume our study of the organic cause of the symptom. We have already seen that the heart itself is not the organ structurally diseased; we have excluded the blood; we have excluded the digestive system; and we have been driven to the nervous system as the seat of the organic mischief. The question remains—In which of the two great nervous systems is the change which leads to the failure seated? Is it in the cerebro-spinal system ; or is it in the great system of organic life—the sympathetic system ?
In my original lecture I took the view that the primary mischief was in the cerebro-spinal system, and was cerebral. In putting forward this view I was influenced by the idea that, because the disorder was excited by certain acts which we call mental, therefore the cause of the disorder was in the cerebrum. This hypothesis carried with it the commonly accepted notion that all mental impressions are received in, and that all mental acts proceed from, the cerebrum ; a notion we cannot now hold with certainty. Our more modern observations lead us back to the view of the illustrious Bichat that the great ganglionic system is, possibly, the seat of all those mental acts which the metaphysician has designated as the emotions, passions, and pure instinctive expressions of man ; the cerebro-spinal being the system of the pure intellectual life,—the life that learns and teaches, and in the highest natures controls even the emotions,—the life that supplies the evidence of the superior gift of conscience and consciousness, and which raises the human so far above the other animal existences.
With this change of theory respecting the functions of the great nervous systems, there must flow change of view in respect to the seat of disorder in cases of intermittent pulse. We have gathered the fact, from direct and unmistakeable evidence, that the primary cause of the phenomenon is shock or debility of those nervous centres which are instinctive or emotional ; and if those centres be the ganglionic centres of the sympathetic system, it follows that they, and not the cerebral organs, are the original seats of the mischief. If they be not, then the prime mischief is situated either in the pneumogastric nerve or in the true nervous centres of the heart itself.
It will help us, in elucidating this part of our subject, to make reference to the most modern view respecting the nervous mechanism of the heart. This is that three sets of nerve structure concentrate on the heart, and are concerned in its action, (a) the cardiac ganglia, (b) the supply from the sympathetic derived from the cervical ganglia of the sympathetic system, (c) the cerebro-spinal nerve, the pneumogastric or vagus.
What is the object of this elaborate nervous mechanism ?
The heart, a contracting and relaxing spiral muscle, is held by the nervous organization in the balance of two powers; or it may be more correct to say, the force liberated in the muscular structure of the heart is regulated by a balance of two nervous powers. The contractile act of the heart is promoted by the true cardiac nervous ganglia, and by the supply from the sympathetic centres ; the contractile act is controlled by the inferior cardiac branches of the vagus. Hence when the vagi are divided, the action of the heart is for a time greatly accelerated : while,