We may summarize by saying that adults, who operate on the level of the symbolic function, will regress normally to the level of visual perception and imagery in the dream; it is at this level that Lewin's dream screen becomes perceivable. When a disturbance of going to sleep occurs, as in febrile disease, or when a dissociation of the ego in waking states takes place, then a further regression to the level of the coenesthetic perception may occur in which the Isakower phenomenon becomes available.

The level of coenesthetic perception belongs to what I would call the experiential world of the primal cavity. It is the world of the deepest security which man ever experiences after birth, in which he rests encompassed and quiescent. It is to this world that man escapes when he feels threatened by pathological conditions in febrile states; also when in the waking state the ego becomes helpless through dissociation, as in toxic conditions. The method of escape has a double mechanism: the withdrawal of cathexis from the sensorium, on one hand, the hypercathexis