A white man, aged 30, a contractor and builder, complained of weakness and constipation. His family history was unimportant, and his past history seemed to have no bearing on the complaint. He had had several attacks of tonsillitis until his tonsils were removed, five years before. He had pleurisy when 19 years of age, with a good convalescence, and he had had pneumonia, malaria and typhoid fever, all of which had occurred more than ten years before the present illness. Nine years before, the appendix had been removed. He had not had previous attacks of appendicitis. The present complaint began five years before with constipation, pain in the legs, and at times spells of weakness. At intervals, he had severe attacks of constipation. A year before he saw me, he discovered that there were worms in the bowel movements, and from then on he found them in nearly every movement.