mentally can be called feeble-minded with certainty” (_16_). The reader should also see the admirable review and discussion of the borderlines on the Binet scale in Chap. II of Wallin's _Problems of Subnormality_. Two descriptions of the scale borderlines in books on mental testing which appeared in 1917 are of interest. In his _Clinical Studies in Feeble-Mindedness_ (p. 76), E. A. Doll says: “By the Binet-Simon method feeble-mindedness is almost always (probably more than 95 times in a hundred) an accurately safe diagnosis when the person examined exhibits a mental age under 12 years with an absolute retardation of more than three years, or a relative retardation of more than 25 per cent.” N. J. Melville, in his _Standard Method of Testing Juvenile Mentality_ (p. 10), says: “Conservative estimates today place the upper limit of feeble-mindedness at least in a legal sense at Binet age ten; others place it at Binet age eleven.... A Binet age score below eleven when accompanied by a sub-age (retardation) of more than three years is usually indicative of serious mental deficiency. Even when accompanied by a slight sub-age score, a Binet age score below eleven may be indicative of potential mental deficiency when the test record reveals a Binet base that is six or more years below the life age.” In 1916 the new Stanford scale appeared and its tests are arranged so that approximately 50% of each age instead of 75%, test at age or above. Even with this lowering of the scale units, Dr. Terman describes his borderline for “definite feeble-mindedness” as below an intelligence quotient of 70. This would mean for his 16-year-old mature borderline a mental age on this scale of XI.2. We have no means of determining to what positions these points on the Stanford scale would correspond on the 1908 or 1911 Binet scales. Dr. Terman says “the adult moron would range from about 7-year to 11-year intelligence” (_57_). Apparently also referring to the Stanford scale, the physicians at the Pediatric Clinic of that university agree with this borderline and say: “morons are such high grade feeble-minded as never at any age acquire a mental age greater than 10 years” (_169_). That there is still need for more caution is evidenced by the statement of a prominent clinician in 1916 that “cases prove ultimately to be feeble-minded since they never develop beyond 12 years intelligence” (_135_). Most interesting perhaps is the fact that Binet and Simon themselves, the collaborators who first formulated the scale for measuring intelligence by mental ages, after their years of experience with the tests came, by rule of thumb, to regard IX as the highest level reached by those testing deficient. Dr. Simon stated the borderline for the mature in this way in a paper read in England in 1914 and published the next year. He said: