The cases in which bloodthirstiness and cannibalism are united with insanity are those which properly fall under the head of Lycanthropy. The instances recorded in the preceding chapter point unmistakably to hallucination accompanying the lust for blood. Jean Grenier, Roulet, and others, were firmly convinced that they had undergone transformation. A disordered condition of mind or body may produce hallucination in a form depending on the character and instincts of the individual. Thus, an ambitious man labouring under monomania will imagine himself to be a king; a covetous man will be plunged in despair, believing himself to be penniless, or exult at the vastness of the treasure which he imagines that he has discovered.
The old man suffering from rheumatism or gout conceives himself to be formed of china or glass, and the foxhunter tallyhos! at each new moon, as though he were following a pack. In like manner, the naturally cruel man, if the least affected in his brain, will suppose himself to be transformed into the most cruel and bloodthirsty animal with which he is acquainted.
The hallucinations under which lycanthropists suffered may have arisen from various causes. The older writers, as Forestus and Burton, regard the were-wolf mania as a species of melancholy madness, and some do not deem it necessary for the patient to believe in his transformation for them to regard him as a lycanthropist.
In the present state of medical knowledge, we know that very different conditions may give rise to hallucinations.
In fever cases the sensibility is so disturbed that the patient is often deceived as to the space occupied by his limbs, and he supposes them to be preternaturally distended or contracted. In the case of typhus, it is not uncommon for the sick person, with deranged nervous system, to believe himself to be double in the bed, or to be severed in half, or to have lost his limbs. He may regard his members as composed of foreign and often fragile materials, as glass, or he may so lose his personality as to suppose himself to have become a woman.
A monomaniac who believes himself to be some one else, seeks to enter into the feelings, thoughts, and habits of the assumed personality, and from the facility with which this is effected, he draws an argument, conclusive to himself, of the reality of the change. He thenceforth speaks of himself under the assumed character, and experiences all its needs, wishes, passions, and the like. The closer the identification becomes, the more confirmed is the monomaniac in his madness, the character of which varies with the temperament of the individual. If the person’s mind be weak, or rude and uncultivated, the tenacity with which he clings to his metamorphosis is feebler, and it becomes more difficult to draw the line between his lucid and insane utterances. Thus Jean Grenier, who laboured under this form of mania, said in his trial much that was true, but it was mixed with the ramblings of insanity.