_Comparison of Short Lines._--Two lines for comparison are drawn in ink side by side on the same sheet of paper, so that they can both be seen at a glance. We have a whole series of such pairs. Between the lines, whose average length is 30 millimetres, there is a variable difference. _Estimation of Weights._--Five little boxes, weighing respectively 3, 6, 9, 12, and 15 grammes, are to be arranged in order of weight. _Memory of Figures._--This test consists in repeating a series of figures immediately after having heard them. _Memory of Phrases._--The child is asked to repeat a phrase of twelve to fifteen words immediately after having heard it. We do not wish to insist on the details of these observations. They are still very incomplete. It will be necessary to experiment for a long time[5] before it will be possible to say exactly what it is that is wanting, or that is wrong, in the mental machinery of the defective. No doubt when the classes for defectives shall be under way, when a great many such children are brought together in conditions which suit the convenience of the experimenters, the latter will be able after persevering effort to see daylight in this matter. In the meantime we must be content with a general survey. But however superficial, however defective, our first attempts may be, they may at least give us a start. Let us see, then, what results have been obtained from our tests. These results clearly separate the tests themselves into two groups. To the one set the defectives furnished replies practically equivalent to those of normal children. To the other, on the contrary, they gave answers which clearly exhibited their retardation, or rather their defect. This difference would be deprived of all significance if any of the tests presented no difficulty to a normal intelligence. But in all cases the difficulty was so great that even the normal made many mistakes, and we can affirm that, whilst for the one set the two groups of children were practically equal, for the other, on the contrary, the inferiority of the defective is quite clear.