In presenting the results of this experiment, the writer is especially indebted to Professor R. S. Woodworth, under whose auspices the investigation was carried out, for his interest and advice; and to Dr. Leta S. Hollingworth for the suggestion of the problem, practical aid in obtaining subjects, and constant inspiration. She is indebted to the School of Education, Teachers' College, for the provision of operative treatment for the subjects; to Mr. Mark and his officers at Public School 64; and to Superintendent O'Brien of the Manhattan Eye, Ear and Throat Hospital. It must be said that by their hearty and generous cooperation they have contributed in a large measure to whatever value this study may possess. ADENOIDS AND DISEASED TONSILS: THEIR EFFECT UPON GENERAL INTELLIGENCE CHAPTER I. PREVIOUS LITERATURE Concerning the Relation of Nose and Throat Defects to Intelligence There are very few experimental studies of the relation between intelligence and the two defects considered here. There are a few statistical studies, and among earlier writers especially many statements of opinion on the matter. Characteristic of the latter is the following extract from an article in the Boston Medical and Surgical Journal, March, 1886.[1] [1]: F. Hooper, M. D., quoting from a paper by B. Frankel. "... it is a fact that their intelligence may become weakened and their characters changed. They do not progress in their studies at school, are generally at the bottom of the class and remain in it longer than the prescribed time.... That the impairment of intellect and want of energy manifested by these children is real, and not merely in the expression of countenance, is made evident by watching these same children after the growths have been removed. To the gratification and astonishment of the parents and teachers, the children hitherto sluggish and dull of comprehension, now make rapid progress, and their comrades soon cease to make a laughing stock of them." The following quotation from an article by Irving Townsend, M. D., is in the same vein:[2] [2]: Adenoid Growths of the Naso-pharynx. Read before the Homeopathic Medical Society of New York, February, 1895. "Aprosexia is the rather imposing term applied to the imperfect or arrested mental development attributed to this condition. This is denied by some authors, who claim that the dullness of comprehension and inattention are only apparent, and due only to defective hearing. A strong evidence of its reality lies in the fact that these children show most marvelous intellectual development after the removal of the growth, even in cases where deafness is not markedly improved." A most enthusiastic denouncer of adenoids and abnormal tonsils is H. Addington Bruce. Concerning their direful effects upon the intelligence, and the magical results of their removal, he is continually reiterating:[3] [3]: H. Addington Bruce, Psychology and Parenthood, 1916.