This monograph summarizes an extremely careful and interesting study of 1,280 cases of mental defect which was carried out in England under the auspices of the Medical Research Council, the Darwin Trust and the Royal Eastern Counties Institution. The observations of the author were checked by other physicians. Psychologists and social workers took careful histories, made several home visits to each family and performed psychometric tests.
The author recognized that mental deficiency is a matter of degree and that an arbitrary line cannot be drawn between the normal and the abnormal. As each case was studied, special care was given to observation of physical abnormalities, neurologic signs, the family history, the social status and the mental status of the parents and of all available relatives.
There are many tables to indicate the number of cases and the degree of mental deficiency as correlated with each of the factors just cited.