It must be remarked at the outset that all the data are extremely doubtful. Everybody knows how the lives of great men become daubed over with anecdotes and tales, how—in part consciously, in part unconsciously—the facts are enveloped in a tissue of the most wonderful legends, until each great historical figure becomes surrounded by a nimbus. These inventions mingle with the real events; one writer copies them from another; the original documents are lost; and the tale becomes universally accepted as a fact.

Every psychiatrist is well aware that it is not always an easy matter to make certain that there are hallucinations, even when the patients are under our eyes. Neither the testimony of the patients themselves nor that of their guardians is, as a rule, sufficient to exclude the possibility of error; and the physician will, in most cases, form his judgment only upon his own personal observation. When it comes, then, to a notice, by a writer who has copied from some previous writer, of some hallucination that somebody is supposed to have had several centuries ago, the fact cannot but be regarded as dubious. Plutarch, for example, informs us that during the night before the battle of Philippi the ghost of murdered Caesar appeared to Brutus. Are we to accept this as a case of hallucination, without further information, or not? We should like to cross-examine the witness; at least to inquire whence he got his information. But that cannot be done. Here is the whole passage: “It was late one night. The tent of Brutus was dimly lighted, and a deep silence reigned over the whole camp. He himself was sunk in thought, when he suddenly thought he heard somebody coming. He looked toward the door, and saw there a dreadful and extraordinary sight. It was a dismal, frightful figure which silently stood by him. He ventured to ask it, ‘ Who art thou, man or god? What wouldst thou? Why comest thou to me?’ The ghost answered: ‘Thy evil spirit, Brutus. At Philippi thou shalt see me.’ And Brutus without being terrified, answered,’ So be it.’”