The House of Commons in 1802 was committed to a variety of extravagances, but, allowing for these, you have to account for certain evidence that Cowpox had _some_ influence over Smallpox; for you surely do not mean to contend that it had _no_ influence over that disease, and that the evidence before the Committee was a uniform tissue of illusion and delusion. Put thus, it is as difficult to deal with the objection as it is to prove a negative. It is not for me to define the influence of cowpox over smallpox, but for those who believe in its prophylaxy. I should argue that as ill-health leads to ill-health, and as corruption breeds corruption, that inoculated cowpox would generate a habit of body favourable to smallpox, and at the same time tend to excite and intensify other forms of disease. I would also ask, What are the extravagances to be allowed for? When these are determined we may then proceed to discuss what are not extravagant. It is a common form of evasion to make a general confession of guilt in order to avoid the pain of specific and explicit condemnation. It is conceded that the House of Commons in 1802 “committed a variety of extravagances,” and under this appearance of candour the chief extravagance is implicitly re-asserted and carried forward, namely, that inoculated cowpox had an influence adverse to smallpox. In the “variety of extravagances,” few, I suppose, would hesitate to include the asserted annual smallpox mortality of the United Kingdom. Sir Gilbert Blane pronounced it 45,000, while Dr. Lettsom gave it as 36,000--a wide difference in the play of fancy! Dr. Lettsom, who claimed to have paid much attention to figures connected with smallpox, was pleased to convert an extreme London mortality, namely, 3000, into the ordinary mortality, although in some years it fell under 1000. Then estimating the population of London at one million, and the population of the United Kingdom as twelve millions, he multiplied 3000 by 12, and evoked the astounding national death-rate of 36,000 annually from smallpox, all of whom were to be saved by Jenner’s prescription! But whether he had taken the average or even the lowest metropolitan mortality, the computation would have remained grossly fallacious. London overcrowded and pestiferous, was no standard for the general population, urban or rural; and the assumption was monstrous that smallpox, a notoriously sporadic disease, was constant and equally diffused over the land. We are without comprehensive vital statistics for the time in question, but arguing from the London of to-day in continual connection with the provinces, to the London of 1802 in comparative isolation, what do we find? Why, smallpox prevalent in London with little or no smallpox in the country! In the _Pall Mall Gazette_ of 31st May, 1878, we read--