*Dr. Wilkinson – “The Human Body and its Connection with Man.”
According to this explanation, which we cannot hesitate to accept, the heart has a circulation of its own, which gives it a power to maintain its own constancy in the midst of the fluctuations of the blood, and to make it the head, ratio, or balance, as well as the heart, of the too-mobile circulation.
Again, according to this view, the varying quantities of the blood returned upto the heart, find an outlet through the walls of the heart itself, and equilibrium is thus maintained by the coronary vessels; so that the heart, plus the coronaries, equals all the forces of the circulation; while the heart, minus the coronaries, is a comparatively regular force uninfluenced by the general state of the system. Were it not for such provision, the heart would be at the mercy of extraneous influences; the most important organ of the trunk would have no stability, would in the end yield, and be distended into a bladder or membrane, incapable of anything but the most passive recipiency.
Next to the consideration of the circulation of and in the heart, and its nutrition, the next is importance is
THE INNERVATION OF THE HEART,
Or, the nervous circulation or nervous forces which impel and regulate the motion of this wonderful organ. The heart is endowed, above all other organs, with a property which has been termed irritability, by which is meant the capability of being easily excited to movements of contraction alternately with relaxation.
After the heart has been removed from the body, and has ceased to contract, a slight irritation will cause it to execute, not one movement only, but a series of alternate contractions and dilatations, gradually diminishing in vigor until they cease. the contraction begins in the part irritated, and then extends to the rest. And it appears that it is the muscular tissue alone that possesses this peculiar property, for if the parts of the heart experimented upon are connected by the tendons the irritation will not extend through such connection. This irritability is less speedily lost in cold-blooded than in warm-blooded animals. The heart of a frog will go on pulsating for many hours after its removal from the body; and the heart of a surgeon when inflated with air, continues to beat until the auricle absolutely becomes so dry as to rustle during its movements.
Not only will the whole heart continue to beat when removed from the body, but even small and isolated portions will contract and relax with great regularity. Cut the heart lengthwise into two halves, and each half will continue beating. Cut it across, through both auricles and ventricles, and both sections will beat as before. The auricles will persist in their rhythmical action when cut off above the auriculo-ventricular rings, and the apex of the heart will do the same when separated from the rest of the ventricles.
This is one of the spectacles which assail the mind of the student with somewhat of a tremulous awe. The beating of the heart, which from his childhood he has learned to associate, in some mysterious manner, with life and emotion, he here sees occurring under circumstances removed from all possible suggestions of emotion or life. All connection with the spinal cord is served. The brain cannot send to it any voluntary influence. The blood no longer courses through it, to give it motion by contact or lengthwise. What then causes the heart and each separated portion to continue their rhythmical pulsations? This irritability does not depend upon the cerebro-spinal system, for it has been proved that the heart’s action will continue in the body after the brain and spinal cord have been removed. For many years no explanation could be given of this wonderful self- life of the heart. We now know that the heart has a nervous system of its own, as well as a circulation within itself.
In the substance of the heart is a complete little nervous system, consisting of ganglia and nerves, and is not made up of the nerve filaments which come from the pneumogastric nerves. From these ganglia nerves are distributed through its muscular substance. It is to this nervous apparatus that we must ascribe the spontaneous action of the heart; for if any part be served form all connection with the ganglia the pulsations will cease at once, but if the smallest served portion of a heart contains a ganglion the pulsations will continue. In other words, it retains its irritability. The movements during life or death are due to these ganglia. No other ganglia in other parts of the body retain their power after the circulation has been destroyed. In view of this, we might almost believe the fanciful notion that the heart was a sentient organism – a being within a being!
But the most wonderful thing about the heart remains to be told. It pulsates in the embryo long before it contains blood, and long before any nerves have been developed in it – when, indeed, it is nothing but a mass of cells! What is the essential nature of these cells? Does each one possess the property of spontaneous movement? Do we know the nature of the stimuli which causes this movement? And when does this movement begin?
In discussing this question, a certain eloquent writer says” “The essential unity of the rhythmic beat of the heart, and the amoeboid movement of protoplasm, are well shown by the history of the new-born heart. In the chick growing within the egg the hart begins to beat very early, while as yet it is built up of nothing but protoplasmic cells. Many authors, over-jealous, as it seems to me, for the prerogative of nerve-cells, find satisfaction in affirming that these constituent cells of the young heart, though apparently alike in structure, are various, some being potentially nerve-cells, other potentially muscle. To my mind, each and every cell is not only potentially, but actually, both nerve and muscle. So long as they are still cells, that is, still tiny masses of untransformed protoplasm, each enjoys all the powers of life. What befalls them afterwards is not grain, but limitation and loss. Some cells lose the power to move, and so become nerve-cells; other cells lose (to a great extent, at least) the power to originate impulses, and so become muscular. Very interesting is it to watch how the slow, irregular, drawling movements of the primordial protoplasm are gradually transformed and gathered up into the sharp, short stroke of the heart’s beat. We speak, in common language, of the hart of the chick as beginning to beat on the second or third day of incubation. It is then that its beat becomes obvious to our senses as a beat. But, in reality, it never does begin to beat. There is no sharp line of demarcation between the protoplasmic crawl and the true rhythmic spasm; the one, little by little, merges into the other. To borrow an illustration from music, it might naturally be imagined that the matter took place in this wise: We might fancy that the tiny cells were marshalled in their places round the cavity of the heart, as musicians are marshalled in an orchestra, fully equipped with powers of rhythmic pulsation, but quiet and inactive; and then, that at a wave of the wand of the great conductor, at the moment when fuller life was breathed into every cell, all struck up in unison with the heart-beat. We might fancy, I say, that this was how the first stroke was wrought. But it is not so. To gain a true image of the process, we must think of ourselves as listening with eagerness, a long way off, to a multitude of performers assembling together, each playing on the same instrument, but playing in a different way, though all trying to learn the same tune, and all gradually drawing near to us. As we listen to them with stretched ear, coming nearer and nearer, and as, at each moment, more and more performers fall into the one proper time, the initial discordant noise, as it gathers in intensity, also gradually puts on a definite form, and at last there comes a moment when we say, ‘Now I hear them! now I have the tune!’ So it is with the growing heart. Looking at it earnestly with the microscope, we may fancy ourselves witnesses of how the cells, as they assemble together, little by little exchange the all-sided flow of protoplasm for the limited throb of a muscular contraction, gaining in force what they lose in form. And so there will come a time when we can say, ‘Now I can see it beat;’ though in reality it has been beating a long time before.* *Dr. S. Foster – “Wonders of the Heart.”
PATHOLOGICAL DEDUCTIONS.
From a pathological point of view, this peculiar nervous structure of the heart is important. It teaches us that certain diseases of the heart may originate within itself – i.e., are idiopathic. Especially may this be the case with the disorders known as functional or nervous. Thus, in some cases the functions of the body may be perfectly healthy, while the heart is disordered. Its nervous system may be deranged, while that of the body may be in perfect health.
Hale wrote Lectures On Diseases Of The Heart, Materia medica and special therapeutics of the new remedies Volume 1, Materia Medica And Special Therapeutics Of The New Remedies Volume 2, Saw Palmetto: (Sabal Serrulata. Serenoa Serrulata), The Medical, Surgical, and Hygienic Treatment of Diseases of Women, New Remedies: Their Pathogenetic Effects and Therapeutic Application, Ilex Cassine : the aboriginal North American tea, Repertory to the New Remedies with Charles Porter Hart, The Characteristics of the New Remedies, Materia Medica and Special Therapeutics of the New Remedies, The Practice of Medicine, Homoeopathic Materia Medica of the New Remedies: Their Botanical Description etc.