In the last thirty years of the 18th century the accounts of fever in England became more detailed as to its circumstances, and more numerically precise. I shall accordingly bring together all that I can find relevant to fever in London, Liverpool, Newcastle and Chester, and thereafter in those towns, such as Manchester, Leeds, and others in the North, which were specially touched in their public health by the movement known as the Industrial Revolution. Typhus Fever in London, 1770-1800. In the London bills of mortality the item of fevers diminishes steadily during the latter part of the 18th century, the deaths from all causes diminish, the births come nearer to the number of the deaths, and in three years of the last decade they exceed them. This statistical result is doubtless roughly correct; but the bills were becoming more and more inadequate to the whole metropolitan area; and even for the original parishes which they included they have not the same value for fever in the later period as they had for plague at their beginning[236]. On the other hand, from about the year 1770 we begin to have more exact medical accounts of fever in London, which are not indeed numerically exhaustive, but good as samples of what was going on. Whatever improvement there was in the prevalence of typhus fever touched the richer classes. The Paving Act of 1766 is credited with having improved the health of the City, and there were many new streets and squares being built in the west end that were, of course, free from typhus. It is to these desirable residential quarters that the eulogies of Sir John Pringle[237], Dr John Moore[238] and others apply. The slums of London were as yet unimproved, and but little known to the physicians. Lettsom, who was one of the first of his class to visit among the poor in their homes, has much to say of typhus fever; but he is emphatic that it was nearly all an infection of the poor. “In the airy parts of this city,” he writes in 1773, “and in large, open streets, fevers of a putrid tendency rarely arise.... In my practice I have attentively observed that at least forty-eight out of fifty of these fevers have existed in narrow courts and alleys.” The same is remarked by Currie for Liverpool, by Clark for Newcastle, by Percival and Ferriar for Manchester, by Haygarth for Chester, and by Heysham for Carlisle. The quarters of the rich had gradually become detached from those of the poor. I have shown this more especially for Chester, where the old walls made a clear division; but it was general in the second half of the 18th century[239].