These things were, of course, insufficient to account for the special type of the sweat, or for its sudden outbreak, for the first time in history, in September, 1485. There may have been such favouring conditions in London at the time; something of the kind is indeed implied in Henry VII.’s order against the nuisance of the shambles a few years after; but we require a special factor, without which the unsavoury state of the streets, lanes, yards, and ditches, or the crowded state of the houses, would never have come to an issue in so remarkable an infection as the sweating sickness. Common nuisances were the less relevant to the sweat, for the reason that it touched the well-to-do classes most, the classes who suffered least from the “common infection,” or “the poor’s plague,” and were presumably best housed, or located amidst cleanest surroundings. Even within the narrow limits of Old London there were preferences of locality. If the special incidence of the sweat upon the great households of prelates and nobles, and on the families of wealthy citizens, had rested only on the testimony of Dr Caius, who has a theory and a moral to work out, there might have been some reason for the scepticism of Heberden, who questions whether Caius was not probably in error in saying that the sweat spared the poor and the wretched, because he knows of no parallel instance among infective diseases[527]. But the fact is abundantly illustrated in the details, already given, for each of the five English epidemics; and it is confirmed for the continental invasion of 1529, e.g. by Kock, a parish priest of Lübeck, who says that “the poor people, and those living in cellars or garrets were free from the sickness,” and by Renner, of Bremen, who says that it “went most among the rich people[528].” It was, indeed, owing to its being an affliction chiefly of the upper classes that the sweat has been so much heard of. So far as mere numbers went, all the five London epidemics together could not have caused so great a mortality as the plague caused in a single year of Henry VII., namely the year 1500, or in a single year of Henry VIII., such as the year 1513. But these great mortalities from plague, amounting to perhaps a fifth part of the whole London population in a single season, fell mainly, although not of course exclusively, upon the poorer class. The bubo-plague, domesticated on English soil from 1348 to 1666, was emphatically the “poor’s plague,” and, as such, it illustrated the usual law of infective disease, namely that it specially befell those who were the worst housed, the worst fed, the hardest pressed in the struggle, and the least able to find the means of escaping to the country when the infection in the city gave warning of an outbreak on the approach of warm weather.