g, but they are in a state of tension in the one case, and of
relaxation in the other. The dream consists of the entire mental life
minus the tension, the effort and the bodily movement. We perceive
still, we remember still, we reason still. All this can abound in the
dream; for abundance, in the domain of the mind, does not mean effort.
What requires an effort is the precision of adjustment. To connect the
sound of a barking dog with the memory of a crowd that murmurs and
shouts requires no effort. But in order that this sound should be
perceived as the barking of a dog, a positive effort must be made. It is
this force that the dreamer lacks. It is by that, and by that alone,
that he is distinguished from the waking man.

From this essential difference can be drawn a great many others. We can
come to understand the chief characteristics of the dream. But I can
only outline the scheme of this study. It depends especially upon three
points, which are: the incoherence of dreams, the abolition of the sense
of duration that often appears to be manifested in dreams, and, finally,
the order in which the memories present themselves to the dreamer,
contending for the sensations present where they are to be embodied.

The incoherence of the dream seems to me easy enough to explain. As it
is characteristic of the dream not to demand a complete adjustment
between the memory image and the sensation, but, on the contrary, to
allow some play between them, very different memories can suit the same
sensation. For example, there may be in the field of vision a green spot
with white points. This might be a lawn spangled with white flowers. It
might be a billiard-table with its balls. It might be a host of other
things besides. These different memory images, all capable of utilizing
the same sensation, chase after it. Sometimes they attain it, one after
the other. And so the lawn becomes a billiard-table, and we watch these
extraordinary transformations. Often it is at the same time, and
altogether that these memory images join the sensation, and then the
lawn will be a billiard-table. From this come those absurd dreams where
an object remains as it is and at the same time becomes something else.
As I have just said, the mind, confronted by these absurd visions, seeks
an explanation and often thereby aggravates the incoherence.

As for the abolition of the sense of time in many of our dreams, that is
another effect of the same cause. In