Among the lower races of mankind there is always to be found the witch-doctor, who claims to have mysterious powers, and to be able to hold communication with the spirit-world. Where there is ignorance as to the cause of disease, and the effects that different medicines have on the human body, magical ceremonies and pretensions to supernatural powers are allowed full sway. Fear and anxiety in cases of illness make men eager to believe in any suggested remedy, however absurd it may be. The Dyaks are no exception to the rule. They have their _manangs_, or witch-doctors. The peculiar attribute of the _manang_ is the possession of mysterious powers over the spirits, rather than any special knowledge of medicines. There is often some small idea of the use of certain simple herbal remedies, but it is not on this knowledge that his importance depends. The great function of the _manang_ is to defeat and drive away the malignant spirits which cause sickness and death. All maladies are supposed to be inflicted by the passing or the touch of demons, who are enemies to mankind. The Dyak description of most diseases is _pansa utai_, literally “something passed him.” A spirit passed him and struck him. In accordance with this idea of disease, the only person who can cure the sick man is the one who can cope with the unseen evil spirit. The _manang_ claims to be able to do this. He can charm or persuade or kill the evil spirit and rescue the departing soul from his cruel clutches. When called in to attend a patient, he, in company with other medicine-men, goes through a performance called _Pelian_. There are different varieties of this ceremony, according to the disease and the amount of the fees paid. _Manangs_ are generally called to their profession by a revelation made to them in dreams by some spirit. Each _manang_, therefore, claims to have a familiar spirit, whom he can call to his aid when necessary. When a person receives a call from the spirit, he bids adieu for a while to his relatives, abandons his former occupations, and attaches himself to some other experienced _manang_, who, for a consideration, will take him in hand and instruct him in the incantations, a knowledge of which is necessary for his calling. The _manang_ looks upon a sick person as in the power of an evil spirit. As long as that spirit remains in possession, the patient cannot recover. He bids it depart. If it be obstinate and will not go, he summons his own familiar spirit to his aid. If the evil spirit still refuse to go, then the _manang_ admits his inability to deal with the case alone, and several other _manangs_ are called to his aid.