Revery is a natural condition, so common to children that they are hardly able to distinguish between reports from the external world and images presented by their imagination. But revery is a common experience of the human race in all stages of development. It differs from abstraction in the fact that the latter is the intense pursuit of a train of reasoning or observation, which absorbs the mind to such an extent that there is no attention left for the reports of the senses. Hence the abstracted man neither looks nor listens, and a noise or an impulse, far greater than would suffice to awaken the same man if asleep, may be insufficient to divert him from the train of thought which he pursues. Revery is literally day-dreaming. It is not reasoning. The image-making faculty is set free and it runs on. The mind is scarcely attentive, hardly conscious, and the tear may come to the eye, or the smile to the lip, so that in a crowded street-car, or even in an assembly, attention may be attracted to one who is wholly unconscious of the same. A person may imagine himself other than he is, derive pleasure from the change, and thus pass an hour or morning. In revery we frequently become practical somnambulists; that is, speak audible words that we would not have uttered on any account, strike blows, move articles, gesticulate, and do many other things, sometimes with the effect of immediately recalling us to a knowledge of the situation, when we, as well as others, are amused, but often without being aware of being noticed. In extreme cases the only distinctions between revery and dreaming sleep are regular breathing and the suspension of the senses which accompany the latter.
The passage from revery into dreaming sleep is to be scrutinized, as the line of demarcation is less than the
