Here, as among other primitive tribes, illness is caused by a witch putting something into the body that ought not to be there. The witch-doctor locates and, by a sleight of hand, removes a bone, or worm, or spider, when the patient recovers. Although the witchdoctor knows that his surgery is a deception, and his patient may at least suspect as much, both firmly believe in its efficacy. (The symbolic action convinces the unconscious that the 'bad penis' etc., has gone.)