Probably{278} the only medical work published in America during the seventeenth century was _A Brief Rule to Guide the Common People of New England how to Treat Them-selves and Others in the Small-pocks or Measels_. This was printed and sold in 1677, by John Foster, of Boston. It was printed upon one side of a single sheet in double columns, and described both of these diseases as due to the blood endeavoring to recover a new form and state. The old English distinction between physician and surgeon was for many years quite generally preserved, but could not persist, because of the different conditions under which men practiced. During this century, also, a number of midwives made excellent practitioners,--among them the wife of Dr. Fuller, one of the _May Flower_ pilgrims. Those colonial days, however, seem to have been free from the ravages of itinerant specialists and charlatans, who so abundantly infested Europe at the time. It is also to the everlasting credit of the American profession that it took no part in the horrible delusions and scandalous transactions connected with the Salem witchcraft. By the beginning of the eighteenth century the population of the United States was about three hundred thousand whites; by the end of the century it had increased to a total of about four millions. During this century a larger proportion of educated medical men came from abroad and settled in various parts of the country, while the Colonial and the Revolutionary Wars offered ample opportunity for the development and study of military medicine and surgery. Commerce between the two continents increased; communication became more free, and the people of the Old World and the New were constantly brought into closer relation. The most lively medical controversy of the century was, probably, that excited over the introduction of vaccination against small-pox. In previous sketches I have had to intimate that the greatest enemy of the medical profession in time past has been the clergy. In this{279} particular instance, however, it was to the Rev. Cotton Mather, of Boston, that the profession is largely indebted for the favor with which the new method was received in this country. In 1721 he called the attention of various American physicians to the method, then in vogue in Turkey, of inoculation with virus from the active disease. Dr. Boylston, of Brookline, Mass., who settled in Boston, corresponded with members of the British Royal Society and finally determined to put the method to actual proof. In 1721 he inoculated his own son with the virus of natural small-pox, and within the next year had inoculated two hundred and forty-seven persons, of whom about two per cent, died of the disease; while, of nearly six thousand persons attacked by the disease in the natural way, more than fourteen per cent. died. In spite of this, the man and the method were violently attacked by the people and the