Book II SXPIIILIS 155

order to carry on the work of the waking hours, and it is also
called forth by the rays of the sun. 'This natural heat to some
extent comforted those members and dissipated the windy
elements which were stretching and tormenting the muscles and
nerves; moreover it concocted (digested) the substance. At
night, however, the heat retreats within the body and abandons
the members for whose benefit nature demands it during the
day. For this reason the pains were more active at night and
there were greater distensions, because the substance was de—
prived of the heat which fomented it and dissipated the windy
elements.

In the course of years, however, there has come about a cer—
tain alteration in this disease. Since the original disposing
cause which had been in the air had now ceased to exist, the
disease had no other means of propagating itself than by con—
tagion from one person to another, and hence it was by this
means that it persisted. For every contagion, in proportion
to its distance from its principle and original source, becomes
drier and more earthy on account of the adustion that is always
combined with it. / For this reason the contagions of the earliest
period, inasmuch as they were close to their place of origin and
principle, were observed to be more foul and of fatter substance,
and caused more pustules but fewer pains.  But the contagions
of the following years, being more inflamed and denser, caused
fewer pustules but more pains.  For as, in the beginning, where
there were more pustules there was observed to be less pain,
so, later, where there were fewer pustules there was more pain.
Furthermore, in recent years, as if the contagion were now in
its old age and its substance had become very densely com—
pacted, a still greater change has come about, for many gum—
mata appear, but very few pustules, and those drier, while
there are hardly any pains, or far less severe; because the sub—
stance, on aecount of its density, very readily forms into gum—
mata, but is not readily driven out to the skin, nor does it readily
settle about the muscles. But whenever anything does come
out to the skin, it is a kind of thin phlegm which has aecquired a.
saline quality from adustion; hence, when conveyed to the roots
of the hairs on the body, it consumes their proper nourishment,
and the hairs soon fall out, as happens in porrigo,5* alopecia,
and dry achores. / Moreover it may be that now in this disease
the same thing happens as in cases of alphuss?; for then, when