eitschrift fuer Ethnologie_,
Heft 2 and 3, 1899, p. 216). From another side, Seler, the
distinguished authority on Mexican antiquity, shows (_Zeitschrift
fuer Ethnologie_, 1895, Heft 5, p. 449) that the ancient Mexicans
were acquainted with a disease which, as they described it, might
well have been syphilis. It is obvious, however, that while the
difficulty of demonstrating syphilitic diseased bones in America
is as great as in Europe, the demonstration, however complete,
would not suffice to show that the disease had not already an
existence also in the Old World. The plausible theory of Ayala
that fifteenth century syphilis was a virulent recrudescence of
an ancient disease has frequently been revived in more modern
times. Thus J. Knott ("The Origin of Syphilis," _New York Medical
Journal_, October 31, 1908) suggests that though not new in
fifteenth century Europe, it was then imported afresh in a form
rendered more aggravated by coming from an exotic race, as is
believed often to be the case.

It was in the eighteenth century that Jean Astruc began the
rehabilitation of the belief that syphilis is really a
comparatively modern disease of American origin, and since then
various authorities of weight have given their adherence to this
view. It is to the energy and learning of Dr. Iwan Bloch, of
Berlin (the first volume of whose important work, _Der Ursprung
der Syphilis_, 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.