History.—Martin A. was born in August, 1908, in a small settlement in the woods of northeastern Maine and had always lived there. His parents were healthy. Four other children were alive and well; two had died in infancy of indigestion. There had been no miscarriages.
Martin was born at full term, after a normal labor. He was nursed for eighteen months and then given a general diet. He had measles when he was a year old and whooping cough when he was 4 years old. Otherwise he had always been well.
When he was 5 years old, he began to complain of being tired. He did not look well and became very pale, the skin taking on a yellowish tinge. He did not feel well enough to go to school, but was not confined to bed. He improved somewhat after six months, but soon relapsed. Since then his general