"Comparing the first period after the operation with the period before, it is found that only about one-third showed improvement, and a little over half were doing poorer work. By comparing an average of _all_ work done subsequent to the operation with what was done before, it became evident that improvement in school work is not often observed until after a year from the date of the operation." In the cases that had records for twenty months, 16 show that better work was done in the second period after the operation than in the period before. TABLE A Table showing where improvement begins. _Per Cent of cases showing improvement_ Period 1 Period 2 Period 3 Based on 31 cases 32.2 Based on 18 cases 33.3 66.6 Based on 11 cases 36.3 63.5 100 Based on all groups 33.9 65. 100 These cases were compared with a control group chosen at random. They comprised a total of 100 children who had records for four consecutive school years. TABLE B Table showing how time of improvement of "operated cases" compares with improvement among children at random. Period 1 Period 2 Period 3 A--Per cent of 31 cases 32.2 (operated upon) Per cent of 100 children 42 at random B--Per cent of 18 children--20 33.3 66.6 months (operated upon) Per cent of 100 children at 42 41 random C--Per cent of 11 cases for 30 36.3 63.5 100 months (operated upon) Per cent of 100 children at 42 41 41 random "... Immediately after operation, there seems to be a dropping off in the quality of school work done," but thereafter a marked improvement while the random group shows a comparatively static percentage of improvement from year to year. The conclusion of the author is: "Here seems good reason to believe that the removal of diseased tonsils and adenoids is a factor in beneficially influencing the mental life of the school child. Not only is the health impaired by failure to remove these diseased parts but the mental life and activity of the child as well."