In analogy with what experimental pathology has taught us about the microbes of cholera and tuberculosis, the bacillus niger does not seem to thrive on animals, though several exceptions to this rule are to be found, and as the tuberculosis bacillus is exceedingly common amongst cows, so may be pointed out the great diffusion of bacillus niger infection amongst old donkeys (Rosina). I do not believe, though, that here, as with the cows, one can speak of spontaneous infection—the virus has, in the case of the old donkey, more probably been introduced into the blood through a flogged back. Dogs seem, after a long contact with infected individuals, to be receptive of contagion (Puck).
Bacillus niger originates in the heart—there is no doubt about that—the disorders of the brain are secondary. The explanation why the seat of the evil has been supposed to be the brain is natural enough, because as a rule it is only since the infection has spread to the brain that the malady can be diagnosed. So long as bacillus niger has only attacked the heart, the diagnosis is much more difficult. The nature of the evil can, however, here, as in certain forms of tuberculosis, be easily enough detected at the back of the eyes. This is probably in relation with the morbid alteration of the organ of sight, which characterises the bacillus niger infection—the patient sees life as it is; when, on the contrary, as is well known, in the normal eye the vision of the outer world is reflected through certain media, illusions and never-dying hope, before it is transferred through the optic nerve to the brain.
As with microbes of the before-mentioned diseases, bacillus niger is also exceedingly tenacious of life. Its virulence can be temporarily reduced by alcohol, ink, and music. As for alcohol, its effect is indubitable, but unfortunately of very short duration. The microbe very soon—indeed, already the next morning, according to all experimentalists—regains its full vigour, and its temporary inactivity seems rather to have increased its virulence instead of decreasing it. Like most of the other antimicrobic agents, alcohol is in itself a deadly poison, and its application in the treatment of the disease is therefore very limited. It is to be used with the greatest precaution, for there are numerous instances of the individual having followed his microbe to the grave.
May I here mention en passant a harmless old quack remedy—the common practice of smoking out the microbe. The home of the tobacco-plant is the same land where the poppy of oblivion blossoms, the silent shores between which flows the stream of Lethe. The fragrance of its leaf has deadened the microbe in more than one diseased brain, the clouds from an old pipe have hidden the reality from more than one sorrowful eye. (Do you remember Rodolphe in Henri Murger's Vie de Bohème?)
Ink as a bactericide is less known, but worth consideration. I know of a case, to which I shall return later, where a momentary amelioration was produced by an ink-cure. Contrary to alcohol, this specific can be used without any danger whatever to the individual himself—the danger being limited to his surroundings. The microbe is dipped in the ink-stand, and fixed on paper to dry. It maintains, however, its virulence long enough, and can, transplanted in a fertile soil, regain its vigour and grow. The preparation must, therefore, be strictly locked up in the writing-desk, which now and then must be disinfected, the surest disinfectant being here, as always, fire.
As for music, this treatment was known even in the childhood of science; it was already highly esteemed by the ancients—hypochondria is, as is well known, one of the oldest of all diseases; it resounds already in the choruses of Sophocles and Euripides. The new world of bacteriology was then undreamt of, but the discoveries of thousands of years have done no more than verify the experience of the ancients. Music still remains the greatest consoler of sorrow-stricken man. Still to-day Saul seeks relief for his sombre soul from David's harp, still to-day does Orpheus conquer the shades of Hades by the sound of his lute; still to-day the song calls out for the Eurydice of our longing.
As was to be expected, the discovery of the microbe of hypochondria gave quite a new direction to the study of the treatment of this disease. To relate here the far-reaching experiences which followed the isolation of the bacillus niger would carry us too far—enough to say that the results of these investigations have unfortunately up till now been hopelessly negative. We, however, find it expedient to mention in a few words the experiments in air-therapeutics by which the discoverer of the microbe hoped to find a remedy for the evil—true that the result was even here negative, but there is a certain amount of interest still attached to these experiments which, pursued with more patience, might perhaps have led to a more satisfactory result. Starting from the analogy between the bacillus niger infection and tuberculosis, the doctor emitted his hypothesis of a region of immunity from hypochondria as well as from consumption, of a possibility of finding in the pure air of the high altitudes a medium where the development of bacillus niger in the mind would cease, as well as the development of the tuberculosis-bacilli in the lungs. It was in the domain of experimental pathology—the field where Pasteur and Koch reaped their laurels—that the solution of the problem was to be looked for, and the bacterium in question living almost exclusively on mankind, the suitable animal for experiment had in this case necessarily to be a man. The doctor had for several years attended an individual affected with the complaint in question. It was a fine case. We quote here from the notes of the doctor: "Man about thirty. The patient maintains an obstinate silence as to the origin of his sufferings; it is, however, evident that the evil dates from several years back. External examination nothing remarkable—on the contrary. Big dog at his heels. Energy but little developed. Active impulses wanting. Ambition rudimentary. Intelligence mediocre—maybe slightly above. Sense of humour well defined, as usual in these cases. Sensibility abnormally developed. Heart perhaps rather large. Tendency for idealism. Patient has hallucinations—fancies, for instance, he is surrounded by people who suffer and hunger; imagines seeing all sorts of animals oppressed and tortured to death." The doctor had in vain prescribed several things in order to calm and distract his diseased mind, rest-cure in Anacapri for a whole year; earthquake in Ischia, cholera in Naples, etc. etc., but without any enduring result. Returned to Paris, the patient had, though with visible aversion, gone through a cure of ink-treatment, and in the beginning had felt a little better for it, but had soon fallen back to his normal condition of hopeless dejection. The doctor was at his wit's end, and began to be bored to death by the continual lamentations of his patient. The unfortunate man was perpetually hanging about in the doctor's consulting-room, and ended by taking up nearly his whole day, to the great detriment of his other practice. It was then the doctor communicated to his patient his hypothesis of the possibility of a region of immunity from hypochondria, as from consumption, and the desirability of finding a fitting animal for experiment, for the purpose of studying the influence of high altitudes on hypochondria.
The patient placed himself at the doctor's absolute disposal.
On the top of Mont Blanc (4810 mètres) the doctor still found a considerable quantity of microbes in the thoughts of his patient. The patient complained that he felt so small and forlorn up there on the pinnacles of Nature's temple, where all around him the Alps raised their marble-shining arch of triumph over the silent cloud-heavy earth. With awe he bent his eyes before the beaming majesty of the sun, where, indomitable and unconscious, the Almighty Ruler trod his course over the shade and light of the valleys, over the sorrow and joy of man.