During the last decade or two there has been a growing interest among physicians in defects of the nose and throat. This interest has centered in part upon those two afflictions of childhood—adenoids and diseased tonsils,—or even tonsils that are merely enlarged. There is no doubt of the physical handicap borne by a child who is possessed of them. As a seat of inflammation, a source of infection, a hindrance to proper breathing,—in a multitude of ways they have seemed to deserve the verdict,—"Have them out." Many physicians, to be sure, have cautioned against the wholesale removal of tonsils, saying that tonsils which are large in early childhood very commonly are absorbed at an early age.

But it is not my purpose to discuss the question of the efficacy of removing adenoids and tonsils. The aim of this study is, rather, to determine experimentally whether or not there exists any causal relation between defect in this respect and lowering of intelligence level. One hears statements made both pro and con by physicians and laymen but there has been little experimental proof. It would seem to be rather useful for a physician to know in advance with how much probability of correctness he is speaking, when he advises a mother that the removal of adenoids and tonsils from the throat of her backward child will make him "bright." The question in the present case, however, is broader than that of relation between these afflictions and mental defect. We are inquiring not merely whether adenoids and tonsils are causes of sub normality or dullness, but also whether they tend to lower the intelligence quotient in general however high it may be. Would the mentally normal child with adenoids and tonsils have been superior without them, and would the superior child have been still more superior? What is the relation between adenoids and tonsils, and intelligence?

The method employed in the present experiment would seem to give it value from the point of view of the clinical psychologist. With the present emphasis upon exactitude in mental testing, investigators have become interested in problem of the constancy of the I.Q. Adenoids and abnormal tonsils have been suggested as possible factors affecting this constancy. The results of the experiment should throw some light on the question.

It should be understood that this study is concerned with general intelligence, and not with the child's efficiency as a member of society. The latter question is much broader than the one we are investigating. It includes not only intelligence, but physical state, emotional make-up, volition: in short, the personality as a whole. Success in school work for example, depends upon all of these factors. For that reason, the results to be reported here, cannot be interpreted as applying to this broader conception. We cannot say at the end whether or not the physical defects under consideration affect the child's success as a member of society. We hope to be able, however, to determine their effect upon one element of that success, namely intelligence.

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.