Thus it has been discovered that similar phenomena are occasionally observed in typhus and nervous fevers. First the patients fancy they feel somebody breathing by their side, or blowing cold air upon their head; after long unconsciousness they are apt to imagine that they are double, and have been known to hesitate where to carry the spoon containing their medicine. In still more marked cases, persons who have suffered from the effects of some great calamity, and have thus been brought to the verge of the grave, have even acted two different individualities, of which one was pious and the other impious, or one speaking the patient's native tongue and the other a foreign language. As they recovered and as the return of health brought back bodily and mental strength, this dualism also ceased to be exhibited during the paroxysm, and finally disappeared altogether. Possession is generally announced some time beforehand by premonitory symptoms, but the first cause is not always easily ascertained. When we are told that certain cases have originated in a hastily spoken word, a fierce curse or an outburst of passion, we only learn thus what was the first occasion on which the malady has been noticed, but not what was the first cause. This lies almost invariably in moral corruption; the lust of the flesh, the lust of the eye, and the pride of the heart are by far the most frequent sources of the frightful disease. Occasionally a very great and sudden grief, like the unexpected death of a beloved person, or too great familiarity with evil thoughts in books or in conversation, produce the same effect--in fact all the various causes which result in insanity may produce also possession. Nor must serious bodily injuries be forgotten. A student of the University of Halle considered himself possessed, and the case puzzled experienced physicians for some time, till it was ascertained that he had received a violent blow upon the head, which required trepanning. Before the operation could be undertaken, however, matter began to ooze out from the ear, and he suddenly was relieved from the paroxysms and all thoughts of possession. Convents are naturally very frequently scenes of possession--the inmates are either troubled by bitter remorse for sins which have led them to seek refuge in a holy place, where they cannot find peace, or they succumb to the rigor of severe discipline and are unable to endure the constant privation of food or sleep. The sin against the Holy Ghost, which unfortunate persons have imputed to themselves, has produced many a case of possession. When the mind is thus predisposed by great anguish of soul or a long-continued inward struggle, the most trifling incident suffices in determining the outbreak of the disease. One patient became possessed because his wife told him to go to the Devil, and another because he had in jest exorcised a demon in a playmate; now a man curses himself in a moment of