"An important group (of mental defects) is due to adenoid vegetations in the posterior pharynx. Under such conditions of ill health, development is impaired and does not proceed at a normal rate. With ... infected tonsils, which produce a constant toxemia, the child cannot be expected to proceed in his development with normal rapidity." In the medical and psychological literature of the last few years, along with the growth of general discussion into the various phases of the operation itself, we find a general disinclination to take on faith the magic effect of adenectomy and tonsillectomy. This growth of critical spirit has shown itself in statistical investigations, and in studies of pedagogical and mental improvement after operation. The statistical studies of physical defects in the schools reveal almost universally a positive relationship between school retardation and possession of adenoids and diseased tonsils. One of these was conducted by Ayres for the Backward Children Investigation of the Russell Sage Foundation in New York City.[7] The investigators examined the school records of 20,000 children from fifteen schools in Manhattan. Eight thousand of these had been examined by school physicians. The records of the physical examinations showed that 80 per cent of the children who were normal for their grade had physical defects while only about 75 per cent of the retarded children were physically defective. [7]: Psych. Clinic, 1909, 3, 71-77. The Effect of Physical Defect on School Progress. This astonishing result was found upon re tabulation of the data by ages, to be due to the fact that for each defect there is a gradual falling off in frequency from the age of six up to fifteen--eye-defect, only, excepted. Since the retarded children in each grade will be the older children in that grade, and since older children have fewer defects, the retarded children will show a smaller proportion of defect. To overcome this difficulty, Ayres used an age basis instead of a grade basis in interpreting his results. Records of all the children at the ages of 10, 12, 13, and 14 were re tabulated, a group of 3304 children, and rated as dull, normal or bright according to the grade in which they were found. The results were worked out in percentages of a group, and are shown in the following tables: Dull Normal Bright Number of children examined 407 2588 309 Defects per child 1.65 1.30 1.07 Enlarged glands 20 13 6 Defective vision 24 25 29 Defective breathing 15 11 9 Defective teeth 42 40 34 _Hypertrophied tonsils_ _26_ _19_ _12_ _Adenoids_ _15_ _10_ _6_ Other Defects 21 11 11