Heredity: Detecting Poisons at Birth

In Massachusetts, just before a newborn baby is taken home from the hospital he is given a novel goodby: a doctor takes hold of him and jabs a lancet into his heel. From the resulting tiny puncture, the doctor squeezes three drops of blood, one each into circles printed on a piece of filter paper. With a midget bandage stuck on his heel, the baby is ready to leave. There is still one more formality: the mother gets a leaflet explaining the purpose of the jab in the heel and why she should...