Modern ieprologists are capable of understanding the extraordinary horror of leprosy that haunted ancient and medieval man, but they find its present-day persistence peculiar. Leprosy is no longer the mystery it once was, and modern understanding of its causes and cures permits most lepers to lead quite normal lives. The belief that makes its victims unfit for cither the sympathy or the society of other men is supported by more than simple aversion. Both the Bible and the writings of Mohammed endorse the view that the leper is unclean, a creature to be shunned by of all the diseases that beset the human race, leprosy is by far the hardest to bear. It is usually disfiguring, often crippling, and not uncommonly fatal. What distinguishes leprosy from all other ailnents is not the physiological dissolution that its victims must frequently but the fear, horror, and violent loathing it excites in others. As a plague, leprosy reached its zenith in thirteenth and fourteenth century Euro It began to vanish about the middle fifteenth century, and was almost extinct by middle of the sixteenth. Many reasons have been given to account for its decline, but timely development of a diagnostic technique flexible enough to distinguish leprosy from disfiguring diseases is considered the most persuasive. Most authorities believe that or fraction of the innumerable victims of medieval leprophobia were actually suffering leprosy.