this were the case, expect a break in the associations of the impressions, and that a person would remember the colour of the orange without its form?

8. Such a theory offers no explanation of the association of impressions which takes place when they are received at the same period of time. This is a process which plays a very important part in the physiology of the mind, in fact, this contiguous association of impressions, without repetition, is the most important function of memory; thus, the factors of the impressions representing a conversation, consist of the memory of a number of articulate sounds, connected by contiguous association; an impression of a picture consists of certain forms which are contiguously associated with each other, and certain definite colours. Without this contiguous association, forms, tunes, colours, &c., could not differ except within very definite limits.

Those cases which have been related of the loss of

memory of impressions received within a certain period of time, have not been accompanied by a loss of function of any of the faculties. It seems improbable that one function of a faculty should be interfered with, and the other left untouched. Several psychologists have accounted for these cases by the hypothesis that an impression requires a period of time after its reception. for its permanent fixation. This might explain those cases in which the period of time was short, but would hardly apply to those cases in which the loss of memory is one of months or years. Besides, though the patient may even, after recovery from the accident, have no recollection of how it came about, he may, as in a case which has come under my own notice, have the whole flash into his mind when visiting the site of the accident

some years afterwards, thus showing that the impression had been retained, and the recording cells not entirely destroyed. (See Case 5, p. 22.)

9. The above facts are sufficient to show that the theory that the memory occupies the same portion of brain as the perception, is not tenable, and to avoid prolixity and the introduction of processes which have not been already discussed, I have rested satisfied with the above, and hope that the incompatibility will be evident to the reader in perusing the following pages.

The mind is made up of a number of faculties, each of which responds to certain impressions, and influences the mind as a whole to seek after those impressions, and to avoid their negatives. The faculties of any particular individual may be compared with a certain definite, average standard, and according as each is above or below this standard (cæteris paribus) will he possess the capacity of appreciating the impressions which are peculiar to that faculty. For instance, a person possessing the emotional faculties larger than the intellectual will be emotional in character, each particular faculty influencing the mind according to its relative size. An individual, with the acquiring faculties very large, will have the impulse to acquire entering largely into the constitution of his mind, and so influencing his conduct and habits. In the same way, an individual with the intellectual faculties predominating will indulge in intellectual pursuits, and these will be in conformity with the faculty which is most above the average size, thus creating the scientific explorer, the artist, or the musician. When a faculty is stimulated by impressions peculiar to itself, it, for the time being, has its influence over the mind increased, thus temporarily having the

same influence as a larger faculty would have when not stimulated. This predominating influence is probably due to the arterial blood supply, of the portion of the brain which is the seat of the faculty in question, being temporarily increased. The great art of the orator and preacher consists in appealing to the faculties of his hearers so as to excite this temporary predominance. Barristers soon get to know those arguments which appeal specially to the presiding judge.

In making a comparison between the size of the faculties in different persons, there is a very important factor which has to be taken into consideration, and that is, the capacity which the faculties of any particular individual have of emitting nervous force. Nervous force is a product of the cerebral cells, in the same way that bile is a product of the liver cells. Nervous force is used up abundantly in all the conscious and voluntary processes of the mind, but very little, if at all, in those processes which are involuntary. The nervous force varies very considerably in individuals, and at different times in the same individual. Consciousness depends upon the nervous force, and when this gets below the minimum necessary for consciousness, sleep occurs. Where nerve force is predominant, there consciousness is at its height, and the ability for mental and physical exertion is very great. Where nervous force is at a low ebb, either temporarily or permanently, there is a corresponding disinclination for either. What a difference there is between the sprightly, intelligent person in whom nerve force is predominant, and the sleepy, lymphatic individual in whom it is deficient! The nervous force of particular faculties is used up in processes which are individually peculiar

to them, and which will be discussed in the next chapter. Most students must have noticed that it is a relief, when they are becoming mentally tired, to change the subject, that is, to use other faculties than those which have been previously employed. Thus, a man who may be falling asleep over classics may have his attention aroused by changing to mathematics. In a person of average ability, if any of the faculties be not used for a lengthened period, a great desire to exercise them is experienced. A great desire for physical exercise is felt after severe mental labour, and I have noticed that this physical exercise must be of a kind to employ the mental portion of the motor apparatus; thus half an hour's boxing or rowing is more efficient for this purpose than several hours' walking, which often has the effect of tiring the body without renovating the brain. Probably, many cases of sleeplessness are due to the unused faculties supplying an amount of nervous force which is inconsistent with sleep, or the vaso-motor apparatus which regulates the supply of blood to individual faculties has become paralyzed for those faculties, and so there is an undiminished supply of blood to the exhausted brain. The essence of the benefit which accrues to an over-worked mental labourer, on taking a holiday, is due to the change of employment, the abused faculties being allowed to rest, whilst those which were previously unused, are employed with vigour in combination with healthy outdoor exercise. We are often surprised at seeing an over-cautious person act in the most reckless manner, and that at a time when he appeared to be more cautious than usual. Here the faculty of cautiousness has become exhausted, and its influence on the mind

temporarily abrogated, the person acting as if he did not possess the faculty. A student will often find that after he has gone through a lesson more than the usual number of times, which he knows by experience he requires to master it, he is unable to recollect a word; but after a period of time, as a night's rest, he finds that he knows it perfectly. This is due to the nervous force of the faculties employed becoming exhausted, in the process of perceiving the impressions, and they are accordingly not able to give out the requisite amount to revive the impressions, but do so readily the next morning. This is borne out by the fact that it is more likely to take place if the sleep be sound than if it be broken.

A faculty can be increased by exercise; but its function never alters; all artificial associations take place below the plane of consciousness.

The mind has cognizance of the impressions in the sensory memory, through the intellectual faculties, each faculty conveying its portion of the impression to the mind, and the intensity of the memory of an impression is in accordance with the intensity of its perception. Much light is thrown on the processes of the mind, and the relation which they bear to memory, by examining the process by means of which an orator composes a speech, or a musician an opera. An orator is anxious to make his discourse as interesting as possible, in order to obtain the attention of his audience. 'Interesting' is only a relative term. This is well exemplified by the great variety of pursuits and habits. A subject is interesting to any particular person according to whether it stimulates his largest or several of his faculties: the clergyman likes religious music, the