DBook II Sy PHILIS 1593

thickest part of the contagion coagulated in certain localities
and formed gummata.

"TThis contagion was not very readily taken in by the body,
because of the viscosity in which its germs had been buried;
hence there was needed a sort of reciprocal heat in two bodies;
thus somehow the germs became active, and were able to ad—
here to something else and to propagate themselves on nour—
ishment analogous with themselves, but this, being as it were
coagulated, they could not have done unless they had been
heated.

This is also the reason why the contagion remained latent
for so long in the body before it manifested itself unmistakably.
On account of the coldness and density of its substance, it would
ereep on sluggishly, but presently would eat its way out and
attack the solid parts of the body also, because of the sharpness
(virulence) of the germs when they became active in that thick
substance, and putrefaction began its work. First small ulcers
appeared on the sexual organs, because it was in that locality
and mainly from sexual intercourse that the contagion had its
origin and beginning. 'These ulcers were not easy to deal with,
partly because that locality is per se rather unclean, partly
because, since the germs were dispersed hither and thither,
when one part yielded to remedies and healed, in another part
an ulcer would sprout forth. A reason why the pustules very
often invaded the hairy scalp first is that that part of the body
is somehow analogous with the contagion on account of the
foulness and density of the humor by which it is nourished;
another reason is that what evaporates from it rises upwards,
and in every putrefaction much evaporation occurs. In cases
where there were many pustules the pains were less severe, be—
eause a great quantity of substance was being expelled, and at
the same time this was a sign that the substance was more
subtile. On the other hand, when the substance was more
densely compacted, there were many violent attacks of pain
and the pustules were fewer. 'The substance that caused the
pains was not established in the aetual joints, because it was too
dense to be able to penetrate to the joints and therefore settled
for the most part above the nerves and muscles. 'The pain
was felt more at night and at sunset because in the daytime the
natural heat makes for the outer surfaces and the members
that are usually in motion; for nature demands this heat in