xxxiv INTRODUCTION

Fracastorius must not be classed indiscriminately with those
physicians who are made to say in Kipling's poem,

KLiook at the stars when a patient is ill'?,

for he would have looked first at the condition of the patient's
humors; and he resorts to celestial influences only when he tries
to account for a morbid exhalation that might contain the
principium of & contagion.

De Sympathia et Antipathia

"The treatise De Sympathia et Antipathia rerum,' the Intro—
duction to Con(fagion, discusses the attraetion and repulsion
of like for like and unlike, the consensus and dissensus of things,
called by Pliny odia amicitiaeque rerum. I$ has been almost
ignored by writers on Fracastorius, and has certainly no scien—
tific value today, but it is curious evidence of the questions that
such men as he were investigating in the l6th century. In
Contagion, he often says that the analogies of the seminaria
contagionis with one or more of the humors in part account for
the specific character of contagions, and refers the reader to
this Introduction. It is impossible here to do more than indi—
cate the contents of the 24 Chapters, with their numerous illus—
trations from animals, vegetables and minerals, of affinity and
the reverse. ^Molecular attraetion' and 'chemical affinity' are
terms that he would have found useful.  **Everything in Nature
is & manifestation of the power of sympathy between the ele—
ments.. . . What is the principle of that attraction?. . . The early
Atomists explained it by the motion of the atoms flowing from all
substances, but what is the principle of that motion? . . . Where—
ever there is attraction, analogy must be present; for instance,
in a magnet, there must be some latent principle that resembles
iron or a principle in iron.. . . We can account for the energy that
projects missiles from cannon, that modern marvel, by rare—
faction of the atmosphere which acts like the waves of the sea. .. .

: On May 9th, 1546, Bembo wrote from Rome to Fracastorius, at
Trent, addressing him as Fisico al Coneilio a Trento, to thank him
for the treatise De Sympafhia. — On account of gout he has not been
able to take it to Cardinal Farnese, but has sent it by a friend; he
adds that the name of Fracastorius is in great honor at the Papal
eourt. / *"Greet the poet Flaminio for me and the Legates at Trent?.