was published in 1901) that we owe the fullest statement of the evidence in favor of the American origin of syphilis.  Bloch regards Ruy Diaz de Isla, a distinguished Spanish physician, as the weightiest witness for the Indian origin of the disease, and concludes that it was brought to Europe by Columbus’s men from Central America, more precisely from the Island of Haiti, to Spain in 1493 and 1494, and immediately afterwards was spread by the armies of Charles VIII in an epidemic fashion over Italy and the other countries of Europe.

It may be added that even if we have to accept the theory that the central regions of America constitute the place of origin of European syphilis, we still have to recognize that syphilis has spread in the North American continent very much more slowly and partially than it has in Europe, and even at the present day there are American Indian tribes among whom it is unknown.  Holder, on the basis of his own experiences among Indian tribes, as well as of wide inquiries among agency physicians, prepared a table showing that among some thirty tribes and groups of tribes, eighteen were almost or entirely free from venereal disease, while among thirteen it was very prevalent.  Almost without exception, the tribes where syphilis is rare or unknown refuse sexual intercourse with strangers, while those among whom such disease is prevalent are morally lax.  It is the whites who are the source of infection among these tribes (A.B.  Holder, “Gynecic Notes Among the American Indians,” American Journal of Obstetrics, 1892, No. 1).

Syphilis is only one, certainly the most important, of a group of three entirely distinct “venereal diseases” which have only been distinguished in recent times, and so far as their precise nature and causation are concerned, are indeed only to-day beginning to be understood, although two of them were certainly known in antiquity.  It is but seventy years ago since Ricord, the great French syphilologist, following Bassereau, first taught the complete independence of syphilis both from gonorrhoea and soft chancre, at the same time expounding clearly the three stages, primary, secondary and tertiary, through which syphilitic manifestations tend to pass, while the full extent of tertiary syphilitic symptoms is scarcely yet grasped, and it is only to-day beginning to be generally realized that two of the most prevalent and serious diseases of the brain and nervous system—­general paralysis and tabes dorsalis or locomotor ataxia—­have their predominant though not sole and exclusive cause in the invasion of the syphilitic poison many years before.  In 1879 a new stage of more precise knowledge of the venereal diseases began with Neisser’s discovery of the gonococcus which is the specific cause of gonorrhoea.  This was followed a few years later by the discovery by Ducrey and Unna of the bacillus of soft chancre, the least important of the venereal diseases because exclusively local in its effects.