With all our advancement in science the question " What is mind 1" still remains Unanswered, and will probably remain unanswered till the end of time. Like the question " What is force ?" it seems beyond the reach of human intelligence. ' We know something of its manifestations, and a little—very little—of the laws which govern them; that is all. One primary fact is sure; viz., the increase of its powers by exercise. We have also found by experience that certain methods of training are more successful than others, and that a certain order in the presentation of ideas is desirable. The reasons for differences in mental power wholly elude us. We observe that, in general, extraordinary mental deficiencies are accompanied by marked bodily defects; but whether the latter are the cause or the effect of the former, we are totally unable to decide. Elaborate treatises have been written upon mental philosophy. Physiologists have struggled for ages with this question, and nothing but hypothesis has been the result of their labors. The present age has, among its other achievements, demonstrated the fact that many of those formerly considered hopelessly imbecile, are capable of considerable mental development. It needs no argument to convince those familiar with the trials imposed upon parents by the idiocy of a child, that anything which can render these unfortunates capable of even measurably caring for themselves, is worthy of careful attention. It has boon reckoned that between thirty and forty per cent of genuine idiots are capable of beingeducated to some extent. Not unfrequently some particular faculty is developed in a high degree. The writer of this article once knew an idiot, who, although singularly deficient in most mental qualifications, had that of construction very highly developed. He could never lay out or plan work, but he could execute with great precision, and was of much assistance to his father, who was a carpenter. This lad (lad only in appearance, at the time we saw him he was 25 years old) would cut a hole in a plank with a compass-saw nearly as round as it could be described with the compasses. He delighted in work, and was always ready to go to bed as soon as he had eaten his supper. We might mention many other instances, both from hearsay and observation, showing that the minds of idiots frequently possess some faculty or faculties as fully developed, or nearly so, as others more richly endowed by nature. One of the most remarkable cases, and one with which the public is already familiar, is that of Blind Tom, the negro boy pianist. Quite a number of schools and asylums for idiots, are now in successful operation in Europe and America. One of the prominent facts brought to notice in the results of these institutions, is that the majority of imbecile children capable of any improvement at all, may be taught to do and delight in doing simple kinds of labor. As most idiots are meager in stature and of weak constitution, such exercise improves their bodily health, which, of course, reacts favorably upon their mental condition. The qualifications of patience, insight into individual character, and adaptability to mental peculiarities, are even more requisite in teaching these weak minds, than those of ordinary children. Indeed, it has been asserted by many heads of institutions like those mentioned above, that their greatest difficulty has been to find good teachers. It is thought by some, that almost any person capable of teaching average intellects, ought to be competent to teach inferior ones, but such is not the case. We look with great interest upon the humane efforts now making to ameliorate the condition of imbecility; and we have no doubt much that will be valuable to mental science may be obtained by the study of the means by which light is made to dawn on the elouded minds of imbeciles.