When X was about 7 years old, the matter of his difficulties was first taken up, with the family physician, who said he would “grow out of it and be all right.” As years passed, and the child continued to be untaught, the physician finally advised the visit to the Neurological Institute. The teacher’s opinion was that the boy must be feeble-minded, since five different teachers had tried to instruct him in reading and spelling, yet he had failed to read or spell any word, except his name. He could recognize his name among other words, and could _draw_ it fairly well, much as he would draw a house or tree. He could not _spell_ his name. Vision and audition had been tested at the Manhattan Eye and Ear Infirmary, and the report was that no significant defect of eye or ear existed. Motor tests showed the boy to be right-handed, so that interference in word-management, possibly due to change in “handedness,” was eliminated. The developmental history of X as an organism reveals nothing atypical, except defects of speech and difficulty in reading. He was born normally, walked and talked before he was two years old, and was normal in dentition. But he did not _talk plainly_ till he was about 6 years old. He had a speech defect, stuttered, and could not say “l”. His medical history shows that he had whooping cough as a baby; that tonsils and adenoids were removed at the age of 5 years; that he had an abscess in the left ear at the age of 4 years, which lasted about two weeks, but did not impair hearing; that he had diphtheria at the age of 11 years, a bad case, followed by temporary paralysis of the soft palate; that he had never had any convulsion or loss of consciousness; that he had never had chorea, or other disease of the nervous system. Physically he was well developed, measurements on February 14, 1918, being as follows: Standing height, 59.8 inches; sitting height, 29.6 inches; weight (with ordinary clothing on), 86¼ pounds; cranial circumference, 21.2 inches; right grip (Smedley), 20 Kg.; left grip, 18 Kg.; lung capacity (wet spirometer), 130 cubic inches. As for family history, X is the youngest of four siblings, all others of whom learned without difficulty to read and spell. His sister graduated from high school with a state scholarship, went through college, and is now a teacher in a high school. An older brother graduated from the elementary school at 14 years, in spite of the fact that he missed two semesters through illness. He also had a speech defect “about the same as X,” but outgrew it. Another brother had reached 8B by the time he was 13 years old. Of thirteen cousins attending school, only one had ever been “left back.” The mother had graduated at the usual age from common school. The father had been troubled in boyhood by a speech defect, which disappeared. “He could not say certain words and letters.” On this account he did not like school. As an adult he reads the newspapers, and “can write a straight letter.”