It is a matter of common observation that certain portions of the human body are covered with hair while certain others are free. The distribution of hair shows all variations, from that of the hairy-chested person who resembles a great ape to that of the person with a skin as smooth as that of an infant. The average normal man has a dense growth of hair on the head, with a somewhat lessened growth in the pubic region, in the axillas and on the arms and legs. The factors relating to the distribution of hair and its variations are obscure, as is the loss of hair in many cases. While the hair is supposed to cover the entire leg of a normally hairy man (fig. 1, 25 year old man), one often sees hairy men with a more or less sharply outlined area of alopecia on the outer and posterior