Contrary to previous notions, Digitalis must be considered as analogous to Strychnine, Nux vomica, Ignatia, China, Quinine and Iron. To prove that Digitalis has an action analogous to these medicines, I quote from the following authorities: Dr. H. Jones stated, in 1859, that he had become satisfied that Digitalis acted as a “powerful cardiac toner, or stimulator.”
Winogradoff and Traube show, by exact experiment, that Digitalis, if not given to excess, does not diminish, but actually increases, the pressure in the arteries. The former states that Digitalis acts both on the regulating and motor nerves of the heart (the vagi and sympathetic cardiac nerves), and that the degree of pressure in the aortic system is the conjoint result of these two factors. The first action of Digitalis on each is to excite, and the second, to paralyze. If, then, the motor are more stimulated that the regulating nerves, the arterial pressure will be increased; and so it will be if the regulating are enfeebled, while the motor are excited. On the contrary, the arterial pressure diminishes, when the regulating nerves are more strongly excited than the motor.
In a dog, after division of the vagi, the pressure rose, after injection of Digitalis, from 124 to 260, declining in ten minutes to 176, millim. Repetition of the injection speedily arrested the heart’s action. There seems to be a remarkable correspondence between these observations and those of Hofschmidt and Moleschott as to the effect of irritation of the medulla oblongata and spinal cord on the frequency of the pulse. * * * They found that irritation of the medulla oblongata was conducted to the heart through the pneumogastric, and not through the sympathetic nerves; while irritation of the spinal cord was transmitted to the heart through both sets of nerves.
From the above evidence, there seems to be good ground to conclude: (1st) that Digitalis, in the milder degrees of its action, has a stimulating influence upon the heart, acting through the medulla oblongata and spinal cord, or the cardiac nerves preceding therefrom; (2d) that its stronger action has the reverse effect, like galvanism or mechanical irritation, arresting the heart’s movements. How this arrest is produced is not clear. On the one hand, it may be supposed that overstimulus tetanizes the heart, producing such strong contraction that the ventricles no longer relax to admit blood, which, of course, would bring the circulation to a standstill. This view is supported by the fact that, according to Dr. Fuller’s observations and my own, the heart, after death from Digitalis, is found with its cavities firmly contracted, contrasting remarkably with the condition produced by Aconite and Chloroform.* *Jones on the Nervous System, p. 320.
The above observations, by Hanfield Jones, seem to me conclusive as to the primary exciting action of Digitalis. In another place, he alludes to another probable explanation of its fatal action, namely, that “the arrest may be regarded as the result of inhibitory action, the excessive stimulus producing a morbid and depressing effect.” This, however, cannot be set down to its primary action. It is the result of an extreme of primary excitation; just as fatal paralysis may occur as an immediate result of tetanic spasm, caused by Strychnine, as well as from the actual tetanic rigidity, or the primary causes of such a tetanic state.
Dr. Jones also says that “Digitalis tones and strengthens the action of a feeble heart, but lowers that of a vigorous one.” This statement is certainly true, as it is true of the action of all similar medicines.
It is a physiological law, which will hardly be disputed at this day, that there is no such thing as medicinal action increasing the normal vitality of the organism. There may be an apparent increase of the vital forces, but it is only apparent.
Under the action of Nux vomica, in pathogenetic doses, on healthy persons, there appear to be greater muscular power, greater tonicity of the motor nerves and greater activity of the physical actions; but these effects are the results of abnormal irritation, which are sure to be followed by a corresponding unmistakable depression. But if Nux vomica is taken by a person not in good health, whose abnormal condition indicates the use of that medicine, the vital forces are carried up to their normal condition by the pathogenetic force of the medicine, which force is correlated into curative force.
The same may be said of the action of the whole class of restorative medicines, namely, China, Hydrastis, Ignatia, Muriatic acid, Helonias, Iron, Ptelea, Ostrya, Phosphoric acid, etc.
The primary action of Digitalis, however, is of shorter duration than any other medicine. This is due to its peculiar method of action, i.e., its action on a complex system of nerves.
The pathogenetic primary action of this medicine exhausts itself in a few days, and if the toxical or extreme tetanic effects do not appear, the secondary action commences; and this action is apt to be chronic in its character.
When the nervous forces which govern any organ are interfered with, or unduly excited, an impairment of nutrition is the consequence; and in the case of an organ like the heart, which cannot rest, this impaired nutrition is productive of the worse results, not only on the heart itself, but almost every organ in the body.
Very few physicians of either school of medicine prescribe Digitalis, except in diseases of the heart, or in certain dropsical conditions, due to such diseases.
They do not consider that there are many diseased conditions of any or all the organs which may depend on an imperfect state of the circulation, but in which a physical examination of the heart would fail to detect much, if any, abnormal action.
It is the opinion of many of the most eminent pathologists that a weak heart, by failing to supply organs and tissues with a proper supply of blood, becomes a cause of many serious and troublesome disorders.
Let us inquire what would be the effect of a remedy like Digitalis, if given in pathogenetic doses, to a healthy person. As before mentioned, the ordinary medicinal doses of ten or twenty drops of the tincture, or a grain of the crude powdered leaves, would so stimulate, or irritate, the heart that it would throw an increased amount of blood, with unusual force, into every portion of the body. The blood, acting as a stimulant, would increase the normal activity of each organ, until there would obtain an abnormal activity. The pathological condition would be slight, active congestion. The physiological condition would be one of functional irritation. The brain would become more active, and all the mental processes be carried on with increased facility. The lungs would act more forcibly, allowing longer inspiration and expiration. The stomach would feel the effects of the increased supply of blood to its tissues, and a sensation of canine hunger, or heaviness, would result. The liver, irritated by the undue influx of blood, would pour out an unusual quantity of bile, and bilious vomiting and diarrhoea would result. The kidneys, if only slightly congested, would secrete an unusual quantity of watery urine. Even the arteries, under certain circumstances, would be stimulated to forcible contractions.
If, however, a very large quantity of Digitalis be taken, at a single dose, or in rapidly repeated doses, we cause a condition like that mentioned by Dr. H. Bence Jones. He says: “On cutting the cervical portion of the ninth pair, of a warm-blooded animal, the frequency of the heart’s pulsations is remarkably increased; and on tetanizing the extremity of the nerve, which is still, by its cardiac branches, in connection with the heart, its motion is slackened, and may even easily be stopped altogether.”
In other words, a massive or toxical dose of Digitalis tetanizes certain nerves which govern the heart’s action, and also tetanizes the heart itself. This is abundantly proven by the examination of the hearts of men and animals killed by this poison.
Now, it follows that, whether the heart is only partially, or completely, tetanized, the current of blood thrown to the various portions of the body must be partially or wholly arrested. Hence would arise a most complete, overwhelming congestion, or stagnation, which would at once suspend all function, and be the starting point for a series of profound derangements. The brain would suffer with coma; the lungs with asphyxia; the stomach with arrest of digestion; the liver would fail to eliminate bile, and the kidneys, urine. If a large dose of China should be given in this condition, we need not wonder if it cause the results mentioned by Hahnemann.
This proposition will hold good: That a very large dose of medicine will develop secondary symptoms, without causing the primary.
In the case of Digitalis, a massive dose will cause similar conditions to those caused by long-continued small doses, namely, paralysis of the heart and other organs.
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.