The tendency of excess on one side is to provoke to excess on the other, but the extravagance of these popular fables ought to put us in love with homely matter-of-fact--wherein indeed is the true extreme of these frantic inventions. What was the extent of smallpox in England last century is the question. With accuracy, we do not know. The common estimates (when not evolved from inner consciousness) are based on the London Bills of Mortality, and when these Bills are scrutinised we find nothing to justify the opinion that the community was harassed and devastated by smallpox over other ailments. In the first place, we have to remark that the exact population of the metropolis was unknown. Some say it was 500,000 in 1701, and others 700,000. In 1751 it was generally reckoned at 750,000, and in 1801 it was said to be 958,863. Then we have to consider that the increase, whatever it might be, lay only partially within the Bills of Mortality, for several rising quarters were outside the boundaries, and there were extensive exemptions within. Thus, so late as 1818, we find Dr. Burrows writing-- The parishes of Marylebone, Pancras, Chelsea, Kensington, and Paddington, now forming an integral part of the metropolis, and containing a population of 160,000 are not within the Bills of Mortality, and make no returns. Neither are there any returns from St. Paul’s Cathedral, Westminster Abbey, the Temple Church, the Rolls and Lincoln’s Inn Chapels, the Chapter House, the Tower Church, and various other places of worship of the Established Church. Besides, neither Dissenters, Papists or Jews who have burying places of their own, are included in the Bills. Many of the wealthier classes when they die are removed for interment into the country; nor do they appear in the Bills. With omissions so serious, the Bills are obviously worth little as registers of the number of deaths in any year in London; and when we inquire how far they may be trusted as indicating the relative prevalence of certain forms of disease, we find them equally questionable. Dr. Burrows thus describes the method by which the causes of death were ascertained--