Here is a child of nine years of age, who has been selected for a class for defectives because he cannot follow the usual lessons in the elementary school. You, however, doctor, put to him some of your usual questions. You ask the child his name, his age, the occupation and address of his parents; the date, day, month, year; some details about his life; you even ask him to read or count. The replies are given to you quietly and correctly. Are you going to refuse to admit him to the special school, and by what right? You have the notes of one, of two, or of three teachers. He cannot follow; he is still with children of seven years of age, in spite of having been at school for three years. It is evident that he is not an idiot, nor an imbecile, nor even feeble-minded to any great extent. But you have been notified that he is behind other children of his age. There is therefore something peculiar about him. It is not a medical question whether he ought to remain in the ordinary school. The doctor cannot go against the opinions which have been given to him, in order to verify whether the retardation is genuine. To do so, it would be necessary for him to make a comparison with the normal condition. Now this varies according to age. The doctor does not know exactly, to two or three years, the normal condition of the mental faculties; nor, after such and such a period of school attendance, the habitual level of instruction reached. That, however, in such special conditions, is the very problem which faces him. We do not hesitate to express the opinion that, in such circumstances, the doctor would be incapable of estimating the intellectual level of the child. He has no more experience in this matter than any other person. Let a doctor seek to pick out a feeble-minded child from a number of normal ones, and he will find how little he is prepared to make the selection. =Physical Examination of Defectives.=--But it may be asked: "Is not mental debility associated with physical signs which the doctor alone is able to appreciate?" About this question three kinds of facts may be considered: those pertaining to anthropometry, the stigmata of degeneration, and physiognomy. Let us consider in order what help may be derived from these.