the essence of the poison which it produces, and which is
separated so abundantly from the body of the patient, remains
unchanged, it is proteiform in its varieties, from the almost
imperceptible vesicle, unaccompanied by fever, which exists for
some time before it extends its poison inwardly, and then excites
fever and buboes, to the fatal form in which carbuncular
inflammations fall upon the most important viscera.

Such was the form which the plague assumed in the fourteenth
century, for the accompanying chest affection which appeared in
all the countries whereof we have received any account, cannot, on
a comparison with similar and familiar symptoms, be considered as
any other than the inflammation of the lungs of modern medicine, a
disease which at present only appears sporadically, and, owing to
a putrid decomposition of the fluids, is probably combined with
hemorrhages from the vessels of the lungs. Now, as every
carbuncle, whether it be cutaneous or internal, generates in
abundance the matter of contagion which has given rise to it, so,
therefore, must the breath of the affected have been poisonous in
this plague, and on this account its power of contagion
wonderfully increased; wherefore the opinion appears
incontrovertible, that owing to the accumulated numbers of the
diseased, not only individual chambers and houses, but whole
cities were infected, which, moreover, in the Middle Ages, were,
with few exceptions, narrowly built, kept in a filthy state, and
surrounded with stagnant ditches. Flight was, in consequence, of
no avail to the timid; for even though they had sedulously avoided
all communication with the diseased and the suspected, yet their
clothes were saturated with the pestiferous atmosphere, and every
inspiration imparted to them the seeds of the destructive malady,