This direct combination of the memories may be applied to explain somnambulism, which consists really in the working out of an impression, and this is often done very accurately, there being no interference from the mind.

Much light is thrown on mental physiology by the examination of errors, as 'slips of the tongue' and slips in writing, and considerable confirmation of the above views is afforded by them; thus it is easy to understand how an intense becomes substituted for a feeble component, as 'glad' for 'sorry' in a letter of condolence. Another common error is to insert in a letter a word or two of a conversation occurring in the neighbourhood of the writer, which bears no relation to the subject of the epistle. The explanation is obvious. It will be noticed that when a movement, brought about by the direct connection, follows a sensory impulse, there is less tendency for the previous impressions to be brought before the mind than when this is not the case, and the more completely reflex these movements become, the less cognizance the mind has of the exciting impressions, and the impressions excited, the nerve force at last travelling from the sensory to the motor memory entirely below the plane of consciousness.

One of the most extraordinary cases of this kind that I know of, is that of a lady who accepted a proposal of marriage when she intended to refuse it, simply through the addition of one or two small words to her letter. She was so ashamed of having made the mistake that she never undeceived the man, and actually

married him!

When the direct connection acquires great intensity the movement will in many cases be brought about on

application of the usual stimulus, when in direct opposition to the will of the person acted on; thus, I know a medical practitioner who stopped a fight, in which a drunken soldier was taking part, by giving the word of command; the man instantly assumed the attitude of attention.

Practical jokers are aware of this tendency, and there is a story told which is probable enough, though I cannot vouch for the truth of it, of a soldier who was carrying his dinner across a yard, when some person called out, Attention!' with the result that the soldier assumed that attitude, and dropped his dinner into the gutter.

A sailor who has been accustomed to rise in the morning at the call of a bugle, will be wide awake and out of bed in a minute on hearing this call, years after he has retired from the navy.

CHAPTER IX

MEMORY IN THE LOWER ANIMALS

THIS chapter has been written not to record any marvellous instances of the intelligence of animals, illustrations of which are to be found at every performing-dog show, but to show how, like men, animals differ in character, their faculties, and special memories, and to give an outline of these, with appropriate illustrations. Corresponding instances will probably be found in the experience of most people.

Anyone who has had much to do with animals must have noticed that in many respects they have extremely accurate memories.

The general memory seems to be exactly the same in animals as in men, and special memories are developed in the same way, so that a dog will have a memory in accordance with the faculties he possesses.

With regard to the general sensory memory, an animal has usually a good remembrance of its surroundings, the whole impression being recollected, as in man, by means of the special memories. If you throw out some crumbs to the sparrows one day, they are very likely to come the next.

All animals must have good sensory memories, or they would lose their way, and not get back to their homes and lairs, as they are not able to find their way

by the names of streets, etc. In the chapter on Sensory Memory, I have already drawn attention to the fact, that it is only by means of the senses that we gain our information of the external world-a congenitally blind man is quite unable to comprehend the nature of sight, or a congenitally deaf man, hearing. Now it is perfectly certain that many animals possess faculties in a much greater degree than man, as in the case of a bloodhound who is able to trace the scent of a man across a crowded market-place. The sense of smell is much more accurate in savages than it is in civilised races, in whom it is comparatively unimportant. Let us suppose, for example, that there were another race of beings, higher in the scale of development than men but destitute of the sense of smell; these beings would not be able to comprehend that bodies should have properties which could not be recognised by the senses they possessed, especially by beings inferior to themselves in the developmental scale: as it is, a dog smells an object which to us is inodorous and is able to recognise it, and have ideas regarding its properties. Then, supposing man did not possess the sense of smell, he would be unable to understand how a dog could find out where a rat was without seeing or hearing it; and so it would be put down to instinct, as many explainable phenomena are. 'Instinct' is a most unsatisfactory term, and can only be used, like 'functional,' as a cover for ignorance. It seems to me that it is extremely probable that the lower members of the animal kingdom, if they do not possess senses essentially distinct from ours, have them modified to such a degree that this is practically the case. This is rendered probable both by comparative physiology and observation. Thus, if we

find such a gigantic difference between the senses of smell and sight in man, animals, and birds respectively, when their anatomy is so similar, it seems hardly probable that the senses are the same in insects, whose anatomical structure is so different. I cannot conceive how any one, who has at all studied the habits of insects, can say that they are simply living in accordance with a mechanism which has been devised for them, without any modification produced by themselves, that is, like well-constructed clockwork machines. I am perfectly sure, and those who have studied the habits of bees and ants will agree with me, that insects gain by experience and are able to communicate with one another. communication might be made through any of the senses, especially if one were modified for the purpose.

A

Examples of motor memory are found in performing dogs, such as that required for walking about on the hind-legs, giving the paw, etc., besides the ordinary muscular movements required in progression.

The special memories of animals are such as are particularly required by them in the acquisition of food.

The faculty of locality is especially needed by animals, and here we have very good examples of its true function, namely, that of being able to perceive accurately the relative positions of objects. It is absolutely necessary for animals, or they would become. lost in the winding forest, and not be able to make their way back again to their mates and young ones.

Instances of the special memory developed by this faculty are common enough, such as cats or dogs having been taken to a considerable distance, often by train, and yet finding their way home again.

Swallows find their way back to their old nests year