J. F., a healthy looking, well nourished, light haired boy, aged 6 years, with an unusually fair complexion, had had every appearance of vigor previous to the illness reported here.His father, aged 31, was healthy. His mother, aged 28, although apparently healthy, had had a dull pain in her chest and a slight productive cough for at least a year. The patient had one brother two years younger than himself who was well. The history of his grandparents and of collateral members of his family was not available. In his earlier years the patient had had measles and chickenpox. These did not have any evil effects. In infancy he had colitis, which left him with a tendency toward diarrhea and a susceptibility to laxatives of all kinds. The lower bowel had been infested with pinworms almost from infancy, and treatment was difficult and interrupted because ofthe intestinal irritability. In the winter of 1927 he