to the amount of vaccination that may be practised. In this case they illustrate the same principle which so well explains the very different amounts of small-pox mortality in Ireland, Scotland, England, and London, with hardly any difference in the quantity of vaccination. The Royal Commissioners, with all these facts before them or at their command, have made none of these comparisons. They give the figures of small-pox mortality, and either explain them by alleged increase or decrease of vaccination, or argue that, as some other disease—such as measles—did not decrease at the same time or to the same amount, therefore sanitation cannot have influenced small-pox. They never once compare small-pox mortality with general mortality, or with the rest of the group of zymotics, and thus fail to see their wonderfully close agreement—their simultaneous rise and fall, which so clearly shows their subjection to the same influences and proves that no special additional influence can have operated in the case of small-pox. CHAPTER IV TWO GREAT EXPERIMENTS WHICH ARE CONCLUSIVE AGAINST VACCINATION Those who disbelieve in the efficacy of vaccination to protect against small-pox are under the disadvantage that, owing to the practice having been so rapidly adopted by all civilized people, there are no communities who have rejected it while adopting methods of general sanitation, and who have also kept satisfactory records of mortality from various causes. Any such country would have afforded what is termed a “control” or test experiment, the absence of which vitiates all the evidence of the so-called “variolous test” in Jenner’s time, as was so carefully pointed out before the Commission by Dr. Creighton and Professor Crookshank. We do, however, now possess two such tests on a limited, but still a sufficient, scale. The first is that of the town of Leicester, which for the last twenty years has rejected vaccination till it has now almost vanished altogether. The second is that of our Army and Navy, in which, for a quarter of a century, every recruit has been revaccinated, unless he has recently been vaccinated or has had small-pox. In the first we have an almost wholly “unprotected” population of nearly 200,000, which, on the theory of the vaccinators, should have suffered exceptionally from small-pox; in the other we have a picked body of 220,000 men, who, on the evidence of the medical authorities, are as well protected as they know how to make them, and among whom, therefore, small-pox should be almost or quite absent, and small-pox deaths quite unknown. Let us see, then, what has happened in these two cases.