A very excellent discussion of the subject of mental defect, particularly in its grosser aspects, as seen in institutions. An outstanding characteristic of the work is the acceptance of the plan of Lewis to divide the mental defective group into two great classes: the subcultural and the pathological amentias. The pathological amentias are the well known varieties that depend upon some definite pathological process such as syphilis, hydrocephalus, mongolism, tuberose sclerosis, microcephaly; while the subcultural group are constituted of those individuals who present deficiencies in intellectual development, which deficiencies, however, are only such as are found in the normal curve of distribution of intelligence. They present no special pathology. The descriptions are for the most part adequate, though brief, as are the discussions of the various methods of examination, prevention, and treatment. The author is not especially