The number of children suspected of mental deficiency obtained by this method varies extremely from one school to another, independently of the mistakes which are made by the head-masters with lamentable frequency. We have found the proportions varying from 0.2 to 10 per cent., with all the intermediates represented. The average of suspects for ten girls' schools, with an average of 300 pupils, was 3.7 per cent.; for eight boys' schools in the same district, and strictly comparable to the preceding, it was 5.35 per cent. It must be clearly understood that these figures are provisional. They do not correspond to real defectives, but to children _suspected_ of mental deficiency; and, moreover, they do not include the unstable, unless they are also defective. Having made these deductions, one writes to the head-masters, or perhaps summons them to a meeting, in order to ascertain the names of these children and various other particulars. These particulars will refer to three main points: 1. Give the full names and date of birth of the backward children (by two or three years, according to the distinctions given above), and indicate also whether the retardation is explained by irregular attendance, by want of application, or defective intelligence. 2. Indicate the children who, although they do not belong to the preceding category, yet appear to be distinctly abnormal. 3. Indicate also the children who are ill-balanced and rebellious to all discipline in the opinion of several teachers who have had them in their classes. We have already received replies which seem to us instructive, and even carry us beyond the study of the abnormal, as they may throw some light on the psychology of those who are commonly called "dunces." As a general rule, the children classed as retarded are the victims of disease, constitutional debility, or malnutrition. We find included in our lists some who are the children of nomadic parents; some who have been kept from school; some who have attended a religious school, where they learned little but sewing and writing; some who have changed their school too often; some also who are foreigners, and understand little French; and, lastly, some who have been kept back in their studies by unrecognised myopia. Such causes are extrinsic to the child. The personal causes of retardation are defective intelligence, sluggishness of mind, insubordination, an eccentric and excitable nature, a constant want of attention, and, lastly, laziness.