PERMANENCE OF IMPRESSIONS.

31.

but on the following day I had forgotten it again. We may conclude from this, and from other analogous facts, that many things which seem to be erased from our memory are not erased from it in reality; that the impression remains, and that, if we are not conscious of it, it is merely because the secret spring has not been touched which could bring it again under our observation.' - Psychological Inquiries; being a series of Essays intended to illustrate the mutual Relations of the Physical Organization and the Mental Faculties.

CHAPTER X.

DREAMS OF ANIMALS.

VIVIPAROUS AND OVIPAROUS ANIMALS.

ARISTOTLE.

'CONCERNING the sleep and watchfulness of animals:— It is quite manifest that all viviparous animals with feet both sleep and are awake; for all that have eyelids sleep with the eyes closed; and not only men appear to dream, but horses, oxen, sheep, goats, dogs, and all viviparous quadrupeds. Dogs show this by barking in their sleep. It is not quite clear whether oviparous animals dream, but it is quite plain that they sleep.

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'Man sleeps the most of all animals. Infants and young children do not dream at all, but dreaming begins in most at about four or five years old. There have been men and women who have never dreamt at

all; sometimes such persons, when they have advanced in age, begin to dream; this has preceded a change in their body, either for death or infirmity.'-History of Animals.

UNDECIDED QUESTIONS.

PLINY.

'Man, just after his birth, is hardly pressed by sleep for several months, after which he becomes more and more wakeful, day by day. The infant dreams from the very first, for it will suddenly awake with every symptom of alarm, and while asleep will imitate the action of sucking. There are some persons, however, who never dream; indeed, we find instances stated, where it has been a fatal sign for a person to dream who has never done so before. Here we find ourselves invited by a grand field of investigation, and one that is full of alleged proofs on both sides of the question, whether, when the mind is at rest in sleep, it has any foreknowledge of the future, or whether this is not altogether fortuitous, as most other things are? If we were to attempt to decide the question by instances quoted, we should find as many on the one side as the other.

'It is pretty generally agreed that dreams, imme

VOL. II.

D

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DREAMS INDEPENDENT OF THE SOUL.

diately after we have taken wine and food, or when we have just fallen asleep again after waking, have no signification whatever. Indeed, sleep is nothing else than the retiring of the mind into itself. It is quite evident that besides man, horses, dogs, oxen, sheep, and goats have dreams; consequently the same is supposed to be the case with all animals that are viviparous. As to those which are oviparous, it is a matter of uncertainty, though it is equally certain that they do sleep.'—Natural History.

DREAMS OF MEN AND OF ANIMALS.

COUNT DE BUFFON.

'In dreams, one sees perfectly, hears rarely, reasons not at all, feels acutely; images and sensations succeed each other without any comparison or hinging together on the part of the soul. Sensations are experienced, but not ideas, inasmuch as ideas are but the comparison of sensation; dreams, therefore, reside only in the interior material sense, and the soul has nothing to do with them. They partake only of the animal memory-of the material reminiscence. Memory, on the other hand, cannot exist without the idea of time -without the comparison of antecedent with present ideas; and seeing that these ideas do not enter into

ANIMAL INABILITY TO DISTINGUISH.

35

dreams, it appears to be demonstrated that they cannot be either a consequence, or an effect, or a proof of We remember our dreams for the

memory. same reason that we remember the sensations we have only just experienced; and the only difference there is between the animals and ourselves, is, that we perfectly distinguish what belongs to our dreams from what appertains to our ideas, or our real sensations-and this is a comparison, an operation of the memory, into which the idea of time enters. Animals, on the contrary, who are deprived of memory and of this power of comparing spaces of time, are unable to distinguish their dreams from their real sensations, and they believe that what they have dreamed has really happened.

'I believe I have already proved, in what I have written upon the Nature of Man, that animals have not the power to reflect. Now the understanding is not only a faculty of this power of reflection, but is itself the exercise of this power-it is its result, and the means by which it is manifested; only we ought to distinguish in the understanding two different operations, of which the first serves as a foundation for the second, and of necessity precedes it. This first action of the power of reflection is to compare sensations, and out of them to combine ideas; and the second is to compare the ideas themselves, and upon them to found arguments. By the first of these