“It may be observed, that though the fever in the confined habitations of the poor does not rise to the same degree of violence as in jails and hospitals, yet the destruction of the human species occasioned by it must be much greater, from its being so widely spread among a class of people whose number bears a large proportion to that of the whole inhabitants. There are but few of the sick, so far as I have been able to learn, that find their way into the great hospitals in London.” I shall defer the subject of the dwellings of the working class in London until a later stage. The “constitution” in Sydenham’s series which succeeded the febrile one of 1661-64 was “pestilential fever.” It began in the end of 1664, lasted into the spring of 1665, and passed by an easy transition into the plague proper. The bills for those months have very large weekly totals of deaths from “fever,” as well as a good many deaths from “spotted fever,” before they begin to have more than an occasional death from plague. It is this particular form of typhus fever that Bateman had in mind when he wrote, in 1818, “We never see the pestilential fever of Sydenham and Huxham”; although Willan, who preceded him at the Carey Street dispensary, described in 1799 a fever of so fatal a type that it gave rise to the rumour that the plague was back in London. The term “pestilential” was technically applied to a kind of fever a degree worse than the “malignant.” Willis, the earliest of the Restoration authorities on fevers, had three names in an ascending scale of severity--putrid, malignant and pestilential. The putrid fevers were what we might call idiopathic, engendered within the body in some way personal to the individual from “putrefaction” or fermentation of the humours; all the intermittents were included in that class, and the theory of their cure by bark was that the drug corrected putridity. In the malignant and pestilential, an altogether new element came in--the τὸ θεῖον of Hippocrates, the mysterious something which we call infection; and of these two infectious fevers, the malignant was milder than the pestilential[23]. Morton drew out the scale of fevers in an elaborate classification, of which only the last section of continued contagious fevers concerns us at present[24]: { {Fever mostly with sweats and {Simple Malignant Fever {other signs of malignity, but { {without buboes, carbuncles, { {petechiae or miliary rash. Synochus { { {Fever with petechiae, purple {Pestilential Fever {spots, miliaria, morbillous rash { {on the chest. { {Plague {With buboes, carbuncles and { {black spots.