THE MOUNTAIN OF FEARS DOCTOR,” said my shipmate, Dr. Leyden, “have you ever made any especial study of nervous diseases—central nervous diseases—morbid conditions resulting from a derangement of the central cells?” I told him that I had done only such work in this branch as a general practice would require, but that I had observed some few cases of especial interest during a military surgical service in the East, and proceeded to cite one or two instances of mental vagaries resulting from gunshot wounds in the head. Leyden leaned both elbows on the taffrail and listened restlessly. Our little ship swashed through the short sling of the Spanish Main, the Pole star gleaming ahead, the Southern Cross blazing astern, and all about the white, flashing crests of the phosphorescent sea. Usually Leyden was a good listener, but this night he seemed impatient, restive, to such an extent that I finally paused, annoyed, for nothing is so irritating as lack of attention to a solicited reply. “Ach! but those cases are in the line of the ordinary!” he exclaimed. “Pardon me,” I replied, “but the last case I have given was distinctly out of the ordinary.” “I am awkward, Doctor,” said Leyden, apologetically. “I mean that the relations of cause and effect follow the usual course—the histological changes in the cell produced impaired function of the organ and these primary changes were the result of trauma. But have you ever had occasion to observe the reverse of this condition—the action of the organ on the center—like a nightmare, where one has the liver poisoning the central cells——” I interrupted in my turn. Leyden was no doubt a skilled naturalist, a close observer and a man of deep power of thought and analysis, but he was not a physician, had never made a regular study of physiological chemistry, and was, therefore, scarcely in a position to argue with a person who had. “Such cases are not infrequent,” I answered. “The ancient Greeks understood that much, as we see from their terms. ‘Hypochondria’; under the ribs—the liver probably poisoning the brain, if you like; then there is the condition of hysteria often accompanying a movable kidney; the action of certain drugs on special centers——” “Such as cannabis indica?” interrupted Leyden, “which affects the sense of elapsed time and makes the subject happy—or—what is that principle, Doctor, which produces xanthopsia, or yellow vision, and makes one sluggish and depressed?” “Xanthopsia is an early symptom of santonin poisoning,” I answered. “The alkaloid is obtained from the unexpanded flower-heads of the——” “Artemisia maritima—yes—I know the plant—but the active principle might occur elsewhere?” “Possibly——” “It is wonderful,” mused Leyden, in the self-communicative tone that was often difficult to follow—“the microscopic filament that makes or unmakes a man; the minute neurons which carry such a potent impulse—like the flash crossing a continent on a tiny wire to send two great nations to war. The wire is short-circuited, the nation disgraced; the neuron short-circuited, the individual disgraced. Such a thing once happened to me, Doctor. To be continue in this ebook...