There was a certain amount of post-mortem observation in the 18th century, especially in camp sicknesses, by Pringle and others; but there is no trace of intestinal ulceration among their fatal fevers. It was found, however, in the epidemic of 1806 among the troops at Deal, and it is probable that Ferriar’s cases at Manchester about 1804, and Bateman’s cases of continued fever in London from 1804 to 1816, were in some part enteric, although the anatomical test is wanting. That was a period when there was singularly little of the old London fever in the houses of the poorer class. Then came the remarkable “constitution” of relapsing or simple continued fever, from about 1816 to 1828, the relapsing character of which was far more obvious in Ireland and Scotland, than in London, Bristol, or elsewhere in England, but was not altogether unobserved in London, whether in 1817-19 or in 1827-28. The relapsing type disappeared after that for fifteen or twenty years, and was replaced by typhus more maculated than had been seen for many years. But, before the relapsing or simple continued fever disappeared for a time, enteric fever was seen in London in company with it. The chief season of enteric fever in London was the autumn of 1826, following a long period of great drought and heat. The remarkable weather of that season was the same in England, Ireland and Scotland, and is thus described for the last by Christison: “The spring and summer seasons of that year were remarkable for the extraordinary drought and heat which prevailed for many continuous months. No such seasons could be recollected by anybody, and assuredly there has been nothing similar in this country since.... The fine weather set in with the beginning of March, and continued, with scarcely a check, well into the autumn.... The drought prevailed and the heat increased till the middle of June, when a thunderstorm with heavy rain cooled the air for a day or two. But the heat then became greater than ever, and there was continuous sunshine and no rain till after the middle of July, when again there was thunder and rain, after which sun, heat and drought ruled the season once more.” The shade temperature at Edinburgh was 84° Fahr., at 3 p.m. on three successive days of July[346]. The two summers preceding had also been exceptional, that of 1824 having been hot and moist, that of 1825 hot and dry, with dysentery in Dublin.