Consider the sequence of events: the dream pictures are all related, at
least individually, to the conversation in question: microscope, slide,
reflex and "scratchiness" are all so many pictures jig-sawed out from this
very context or apperception-mass. The scratching sensation, we must
suppose, evoked these pictures serially, in the order stated. If these
images were what the psychologist calls "trial percepts," we would expect
from them just what we do find, namely, an increasing degree of
correspondence (relevancy) between the stimulus-idea and the images, as they
appear.[33] Precisely so, the images of microscope, slide, reflex and
scratchy handwriting, as they successively come into focus, conform more and
more to the nature of the stimulus, until the approximation ends in the idea
of an all-absorbing interest in "scratchy" marks. This visual image hardly
reaches precision before it becomes translated and transposed to the tactile
field of my ear; smoothly, as if it were one magic lantern view dissolving
into another. In fine, the presentation of each image in the dream amounts
to a groping effort of the dreamer's nervous system to find a proper
experiential EQUIVALENT for the arriving stimulus. It is a trial-and-error
method of perceiving or apperceiving a stimulus by marshelling associated
ideas; in this case they are serially evoked; (what might be called "oniric
echelon"); in other cases the trial apperceptions are blended smoothly
(oniric fusion) or heaped together in rough-and-tumble fashion, a kind of
confusion (conveniently called "oniric entassement") which testifies
sufficiently to the failures of the Unconscious t o dispose smoothly of
arriving excitations, and so emphasizes; the theory of trial-and-error, as
applied to dreams.