the ganglionary tissue.' Sensation being thus defined, can there be sensation without perception?

It is quite certain that we have many sensations that are not at all perceived, and of which we are, as we say, 'totally unconscious.' They are either so weak or so familiar, or so lost in strong sensations, or so incapable of exciting 'associations' of ideas, that we are not 'conscious' of them in the present, and that we cannot recall them afterwards. This happens when we sleep during a sermon or a lecture; we have the sensation of sounds emitted by some one who speaks; we have no perception of them. This cannot be doubted, because, on the one hand, we do not know what has been read or said; on the other hand, if the sermon or lecture cease suddenly, we awake, which shows that we had the sensation of sounds. Mr. Lewes relates that having gone into an eating-house and found a waiter fast asleep, in the midst of the noise he vainly called him by his name, and by his Christian name, but as soon as he had pronounced the word waiter,' the sleeper awoke, Admiral Codrington, when a midshipman, could not be raised out of a sound sleep except by the word 'signal.' These facts, which have many fellows, show that there may be sensation without perception and sensation accompanied by perception.

'It would be an unfortunate mistake in language which should make it absurd to speak of non-perceived sensations. Perception has been so often confounded with sensation, because they have been constantly mixed up together, that we are astonished when it is said that one can be produced without the other. In spite of verbal difficulties we must get well into our minds that every excitement of a nervous centre produces a sensation, and that the totality of these excitements form general consciousness, or the sense of existence.

'We do not see the stars at noon-day, yet they shine. We do not see the sunbeams playing among the leaves, on a cloudy day, yet it is by these beams that the leaves and all other objects are visible. There is a general illumination from the sun and stars, but of this we are seldom aware, because our attention falls upon the illumined objects, brighter or darker than this

general tone.

There is a sort of analogy to this in the general consciousness which is composed of the sum of sensations excited by the incessant simultaneous action of internal and external stimuli. This forms, as it were, the daylight of our existence. We do not habitually attend to it, because attention falls on those particular sensations of pleasure or of pain, of greater or of less intensity, which usurp a prominence among the objects of the sensitive panorama.

'The amount of light received from the stars may be small, but it is present. The greater glory of the sunlight may render the starlight inappreciable, but it does not render it inoperative. In like manner the amount of sensation received from some of the smaller ganglia may be inappreciable in the presence of more massive influences from other centres, but though inappreciable it cannot be inoperative—it must form an integer in the sum.'1

We can now close this discussion by rejecting the current hypothesis which will have it that a sensation does not exist except it is perceived, without which it is a pure impression. Mr. Lewes points out that in distinguishing sensation from perception he does not make a purely verbal distinction, which would consist in calling that 'sensation' that others call 'impression.' By no means; by sensation he understands the sensibility proper to each centre. The naturalist, he says, knows that there is an enormous difference between the monkey and the oyster, but he also knows that notwithstanding their differences all animals obey the same biological laws. I should like to see the same reform introduced into our physiology of the nervous system. I should wish to see it recognised, that notwithstanding diversities, all nervous centres, in so far as they are centres, have properties and laws in common.

Consciousness, in its general sense, being the sum of all our sensibilities, the overflow of several currents of sensations, it results from this, that in the lower animals endowed with a simple nerv

1 Physiology of Common Life, vol. ii. p. 65.

ous system, the sensitive phenomena are simple, and that by degrees as organization increases in complexity the sensible phenomena become necessarily more complex, and the elements of general consciousness become more numerous. This leads to the examination of the question of the various forms of consciousness.

The unity of the nervous system throughout the whole animal kingdom has been generally recognised, but it is strange that unity of consciousness has not been deduced from it.

The various forms of consciousness or sensibility may be properly grouped under these three titles :-First, systemic consciousness; second, sense-consciousness; thirdly, thought-consciousness.'1

Systemic consciousness, which gives us the principal elements of the sense of existence, includes all the sensations springing from the system of the organic functions in general and in particular. Short of adopting the hypothesis of Descartes upon animal machines, we must admit that the humblest animals have this form of consciousness. Those who reject this conclusion are the dupes of equivocal language, which leads them to suppose that there is some element of thought included in consciousness, and even in sensation. But though every animal must feel, it does not follow that it must think. Let us remark besides the absurdity of the consequences. If a mollusc has no sensation, it would be the same as to the crustacea. If the crab is a machine, the bee, the beaver, the elephant, the dog, and the monkey, are also machines. 'Short of throwing science to the winds, we must admit that all animals have sensations, although they have not each the same form of consciousness.'

Sense-consciousness includes all those sensations derived from the organs of the five senses.

Thought-consciousness includes all those phenomena of thought and emotion with which the psychologist is particularly concerned; all that the physiologist can do is to indicate the relations of this form of consciousness with the lower animals, and

1 Physiology of Common Life, vol. ii. p. 74.

the portions of the nervous system which serve them as organs. As for thought we do not know, and perhaps we never shall know, what it is; nor do we know what life is. But we can learn what are the laws of life and the laws of thought. To the physiologist belongs the former task, to the psychologist the latter.

The insufficiency of the preceding theory may be explained by remembering that Mr. Lewes only intends to place himself in a physiological point of view. Mr. Herbert Spencer and Mr. Bain have made us penetrate much more deeply into the mechanism of human consciousness by showing us this double current of integration and of disintegration which constitute it, the condition of time which imposes itself upon it and gives to it the form of a succession. But Mr. Lewes introduces us into another world, and this example appears to us to show, what we have endeavoured to establish in the introduction, namely, that in psychology the subjective method and the objective method are both equally

necessary.

IV.

The theory of reflex actions attaches itself strongly to the preceding considerations upon unconscious sensations. It is striking and instructive to remark how little French psychology has occupied itself with this matter. Restricted to the facts of consciousness, it has avoided everything which has a physiological appearance. And whilst the invading spirit of physiology led it constantly to extend its domain, and even to come out of it on all sides, psychology, confined within strict limits, allowed many a portion of its territory to escape, and asked nothing. The discussions upon the boundary line of the two sciences, which filled the first half of the nineteenth century, sought to define frontiers which have no existence.

Between psychology and physiology there are no natural boundaries. No doubt a purely physiological act, such as circulation, differs entirely from a purely psychological act, such as deductive reasoning; but there is an entire order of facts, insensible perceptions, reflex actions, instincts, etc., by means of which the two lives mingle and are confounded. This subject might have

been less discussed if it had been better understood that our divisions are to a great extent arbitrary in consequence of the continuity of phenomena: that man distinguishes that which nature mixes, and that, if science is an analysis, the world is a synthesis.

The study of reflex actions is the continuation of that of consciousness. In fact, whilst according to the current theory the sensorium is restricted to the brain, the action which has its centre in the spinal marrow is called reflex, and is considered to be of a totally different nature; the theory of Mr. Lewes, which extends the sensorium to all the nervous centres, only admits that there is a difference of degree between the action of the brain and that of the spinal marrow. To establish that the spinal cord is a sentient centre is his aim, building upon his own experience, upon that of others, and upon the deduction which he draws from them. He wishes to 'give the final blow' to the theory of reflex action, upon which he even casts ridicule. The doctrine of the schools, he says, is this:

1

'Mental nervous actions (acts of volition and sensation) cannot take place without a brain. . . . If you pinch a dog's tail, he cries out. His cry is supposed to indicate a sensation of pain. But the physiologist who would reprove you for having hurt his yelping puppy would quietly assure you that this puppy's cries were no evidence of pain or sensation after its brain had been removed. "Merely reflex, my dear sir," and he would smile at your supposition that an animal without a brain could feel any sensation.'' In support of this doctrine he quotes facts and experiments. 'The researches of Flourens had their time. They were truly striking; the conclusions which he drew from them were commenced in that systematic, derisive, absolute style which characterizes French writers;' hence their European popularity, in spite of the reservations of Müller and Cuvier. Flourens maintains that the animal deprived of brain loses all sensation, all perception, all instinct, and all volition. But the contrary experiences of Bouillaud, Longet, and Dalton have weakened his conclusions.

1 Physiology of Common Life, p. 526.

2 Ibid. vol. ii. pp. 84, 85.