The Northern Sierra and Plains Miwok called bear doctors _sulik müko_. These shamans donned bearskins, but, like their Yuki colleagues, had bears as spirits and exhibited their powers publicly. Like the Yokuts bear doctors, they were thought able to transform themselves bodily into bears. The Miwok relate how a man was hunting in the chaparral south of the Stanislaus when a bear appeared and asked what he was doing. The Indian replied that he was seeking an arrow lost in a shot at a red-headed woodpecker. The bear led him into its cave, kept and taught him for four days, and sent him home with several bears as guides. A white man, married to an Indian woman, instigated the building of a dance-house to give the bear doctor an opportunity to show his alleged powers. The latter accepted, came, walked into the fire, pushed aside the flaming brands and made himself a bed in the coals, arose after a time unharmed, swam, and resumed his human form. The Miwok panther doctor was similarly met and instructed by a panther. He wore no skin and possessed no power of transformation. He did, however, acquire the panther’s ability to hunt, it was thought. In extreme old age he revealed his experiences and then died at once. It is clear that the Miwok panther doctor is merely a shaman who has that animal as his personal guardian spirit, and that except for his power of transformation and the character of his guardian, the Miwok bear doctor does not essentially differ from an ordinary shaman. It seems therefore that the institution of the bear doctor has attained its most extreme form among the Pomo. SUMMARY 1. The origin of bear doctors is assigned by the Pomo to the mythical times before men existed, when birds and mammals possessed human attributes. The first bear doctors arose from a relatively insignificant incident, which led one of the smallest of the birds to develop his magic powers. 2. These powers are believed to be now acquired through the wearing of a special suit which endows its wearer with rapidity of motion and great endurance, but which does not itself actually transport him or perform any act. 3. The powers are received through elaborate ritualistic songs and prayers to certain supernatural beings under whose patronage the doctor operates. These songs are largely sung not by the doctor himself but by an assistant while the doctor performs an elaborate dance with the various parts of the costume preparatory to actually putting them on for the first time. 4. In addition to this constant assistant, the bear doctor must have a female aide, who makes certain parts of his paraphernalia and cooks his special food. He is subject to certain restrictions connected with the menstrual periods of this female aide and his wife, and they, in turn, are subject through him to certain other restrictions. 5. Although all-powerful under ordinary circumstances, a bear doctor apparently loses all his magic power as soon as he is captured.