DREAMS.

Some qualification of the above must be made if dreams are said to be instances of unconscious cerebration; but I do not consider that there is true unconsciousness, and the examples given to show that they regularly take place during sleep are utterly untrustworthy.

Evidence seems to show that the large majority of dreams occur in the period between waking and sleeping-that is, in a state of partial unconsciousness.

Dreams do not appear to occur at all in sound sleepers, but to be especially common in those individuals who sleep lightly.

The law that the permanent intensity of an impression depends upon the amount of consciousness with which that impression is received, is supported by the fact that the majority of dreams are forgotten a minute or two after awaking, their evanescent character being due to the slight amount of consciousness at the time of perception.

Dreams are easily explained by the view previously laid down respecting the memories and the faculties; thus, if the greater number of the faculties be asleep, and a few awake, then the few will perceive impressions peculiar to themselves, and, as before mentioned, the fact of reviving a component will tend to revive the remainder of the impression, and so a complete picture will be formed.

We can ascertain the truth of this by thinking of a dream at the moment of waking, and then analysing it, and trying to think why we should have dreamt in

that way, the constituent impressions can often be found. The peculiar scenes which are met with in dreams are due to the blending of several impressions which are perceived by those faculties in a semi-conscious state; in dreams, the process not being limited by the action of the will, impressions may be revived with such rapidity as to make a period of several years be apparently passed through in a few seconds, and this we find to be the case.

Sometimes, in a dream, persons are able to remember what they had forgotten in the waking state; then the dream usually takes the form of someone coming and telling where the lost article is, the dreamer awaking and finding that such is the case.

In other cases a name is forgotten, and the person is told that if he go to a certain place he will see it written.

Again, in cases of recollection in a dream, everyone, who has dreamt at all, knows that individuals are especially likely to dream about subjects which have been uppermost in the mind during the day. Then the dream, having started with the required subject, arouses trains of thought and previous impressions without any interference from the will, and so may, in exceptional cases, revive the required impression.

Numerous other cases might be related, but they are all similar—namely, a perception of impressions and exaggeration of them, this exaggeration taking place because of the revival of other impressions—a number of impressions being perceived at the same time and blended together.

Some experiments have been made with a view to

ascertain the nature of dreams, and it was found that stimuli of various kinds on the special senses would give rise to dreams in accordance with them.

It is often a subject of great annoyance to overconscientious persons to find that, in their dreams, they commit the most horrible crimes without the least compunction. This is probably due to the moral faculties having probably been more used during the day than any of the others, and so are more in need of rest; they are probably sound asleep, and so do not influence the actions of the other faculties.

SOMNAMBULISM.

Somnambulism is only an acted-out dream, and, in many cases, only a simple action is performed.

The connection between the sensory and motor memories brings about somnambulism. We can imagine that an intense impression would bring about this condition, the faculties being asleep.

It is a well-known fact that when a person has been aroused for a short period of time in the middle of a sound sleep, in order to perform some action and perhaps answer one or two questions, it is not an uncommon occurrence for him to find on waking that he has entirely forgotten being aroused in the night, and, in other cases, only remembers it as a dream; probably the impression has been perceived very feebly. This is the most probable explanation of many of the wonders which have been said to have taken place during sleep, or they may be due to the acting-out of an intense impression.

DOUBLE CONSCIOUSNESS.

It will probably have occurred to most persons, in a slight degree, when out of health, to fancy that they have seen or done something that they are seeing or doing for the first time, before. As this will occur not with one impression only, but with all impressions received at that time, and cases are related in which it has been a permanent condition, it is not due to an erroneous idea. It is probably due to the impressions not reaching the optic thalami at exactly the same time, and so producing a condition of mental squinting.

Many cases are related of a condition of double consciousness, and these will illustrate the fact of memory occupying a definite portion of the brain; and are probably due to some lesion of the track between the left optic thalamus and the cerebrum, recovery being due to an education of the right optic thalamus to a condition in which it is able to take on the functions of both, in the same way as a patient sometimes recovers his speech from the right faculty of language developing to a condition to be able to supply the necessary nervous force. The immense variety of these cases of double consciousness is probably due to different portions of the connecting track being affected; but they all show how groups of impressions supplied by all the senses are destroyed, and not impressions belonging to one sense only, as if the impressions were remembered by a sight or touch centre.

CHAPTER XII

PATHOLOGICAL CONDITIONS IN WHICH THE MEMORY IS AFFECTED

I. GENERAL DIMINUTION OF THE MEMORY.

In all cases in which, by any means whatsoever, there is a loss of nervous force not immediately replaceable, there is a corresponding diminution of the memory.

In cases of congenital idiocy we notice that a very feeble power of retaining impressions is usually possessed. This we should naturally expect from an examination of the brain, which is usually found to be considerably undersized. On this account, those faculties, which were under the average size, would perceive impressions very feebly, and recollect them with equal difficulty.

In idiots we have very strong confirmation of the view that the faculties of the mind are multiple, as we often find, with a general deficiency of mental power, some extraordinary capacity in one particular direction, and this can be explained by supposing that with a general deficiency in the size of most of the faculties, one of them is considerably larger than usual. We find that the function of the faculty in question, when occurring in this way, is exactly the same as in a sane person, and acts in the same way when of propor