Nevertheless, it will be found that this is the case.

Thus organic processes which scarcely make themselves known to the mind in a waking state, may be shown to be the originators of many of our dreams.

This fact can only be explained on the physical side by saying that the special cerebral activities engaged in an act of attention are greatly liberated during sleep by the comparative quiescence of the external senses.

These activities, by co-operating with the faint results of the stimuli coming from the internal organs, serve very materially to increase their effect.
Finally, it is to be observed that, while the centres thus respond with diminished energy to peripheral stimuli, external and internal, they undergo a direct, or "automatic," mode of excitation, being roused into activity independently of an incoming nervous impulse.

This automatic stimulation has been plausibly referred to the action of the products of decomposition accumulating in the cerebral blood-vessels.[77] It is possible that there is something in the nature of this stimulation to account for the force and vividness of its conscious results, that is to say, of dreams.
_The Dream State._ Let us now turn to the psychic side of these conditions, that is to say, to the general character of the mental states known as dreams.