obvious in the variety called "unstable" or "ill-balanced." To sum up, we are of opinion that the defective child usually exhibits the following characters: (1) A retardation of development; (2) a defect of equilibrium--_i.e._, the retardation is more marked in some faculties than in others; (3) individual peculiarities of a pathological kind in the mental powers. If this second theory is correct, there follows a very important practical consequence--namely, that the curriculum drawn up for normal children is very imperfectly suited to the defective. We cannot force the latter to fit the ordinary course. To attempt this would be quite as unreasonable as to make our teaching appeal to the ears of the deaf or the eyes of the blind. The first duty of the teacher is to take account of the faculties already developed, the aptitudes which are already apparent. His work is thankless and difficult; he would be foolish not to take advantage of the indications of nature. If a pupil show a special taste for any subject, it is evidently towards such a line of study that he should be directed. Consequently, in conformity with these ideas, we would reject on principle any programme of special instruction which would rigorously include all the children in a common plan. On the contrary, we would prefer for the defective a scheme which would take the most account of their natural aptitudes. Such considerations lead us to put the following question--What are the most common aptitudes in children of this class? We say "the most common," because we have not to do with a single well-defined type, for there are as many varieties as there are individuals; but in spite of the number of those varieties, which shows the need for individual teaching, it will always be possible to establish categories in which those most nearly alike may be grouped It is also possible that the aptitudes most frequently lacking are always, or almost always, of the same nature. To solve the question which we have just raised, we shall employ two methods-- _The questionnaire._ _Direct observation._ A printed questionnaire containing thirty-eight questions has been distributed through the agency of M. Belot, school inspector, to the heads of all the elementary schools in two districts of Paris--one central, the other suburban. Nothing would be gained by reproducing here the questionnaire, which has served its purpose. We shall simply lay down the conclusions we have reached, after studying the replies with the greatest care.