Lefevre was piqued by that article, and he went to see his patient day after day, in the constant hope of finding a solution of the puzzle that perplexed him.  The direction in which he looked for light will be best suggested by remarking what were his peculiar theory and practice.  Lefevre was not a materialistic physician; indeed, in the opinion of many of his brethren, he erred on the other side, and was too much inclined to mysticism.  It may at least be said that he had an open mind, and a modest estimate of the discoveries of modern medical science.  He had perceived while still a young man (he was now about forty) that all medical practice—­as distinct from surgical—­is inexact and empirical, that, like English common law, it is based merely on custom, and a narrow range of experience; and he had therefore argued that a wider experience and research, especially among decaying nations, might lead to the discovery of a guiding principle in pathology.  That conviction had taken him as medical officer to Egypt and India, where, amid the relics of civilisations half as old as time, he found traditions of a great scientific practice; and thence it had brought him back to study such foreign medical writers as Du Bois-Reymond, Nobili, Matteucci, and Mueller, and to observe the method of the famous physicians of the Salpetriere.  Like the great Charbon, he made nervous and hysterical disorders his specialty, in the treatment of which he was much given to the use of electricity.  He had very pronounced “views,” though he seldom troubled his brethren with them; for he was not of those who can hold a belief firmly only if it is also held by others.

More than a week had passed without discovery or promise of light, when one afternoon he went to the hospital resolved to compass some explanation.

He walked at once, on entering the ward, to the bedside of his puzzling patient, who still lay limp as a dish-clout and drowsy as a sloth.  He tested—­as he had done almost daily—­his nervous and respiratory powers with the exact instruments adapted for the purpose, and then, still unenlightened, he questioned him closely about his sensations.  The young officer answered him with tolerable intelligence.

“I feel,” he ended with saying, “as if all my energy had evaporated,—­and I used to have no end,—­just as a spirit evaporates if it is left open to the air.”

The saying struck Lefevre mightily.  “Energy” stood then to Lefevre as an almost convertible term for “electricity,” and his successful experiments with electricity had opened up to him a vast field of conjecture, into which, on the smallest inflaming hint, he was wont to make an excursion.  Such a hint was the saying of the young officer now, and, as he walked away, he found himself, as it were, knocking at the door of a great discovery.  But the door did not open on that summons, and he resolved straightway to discuss the subject with Julius Courtney, who, though an amateur, had about as complete a knowledge of it as himself, and who could bring to bear, he believed, a finer intelligence.