In the eighteen century, serious thought about the impact of medical intervention concentrated on one question: the merits of inoculation againts smallpox. The procedure was simple: a thread covered with pus from a fresh pock on someone mildly infected with smallpox was pressed into a cut on an arm and on a leg of someone who had not yet had the disease. This usually resulted in avery mild case of smallpox, from which the individual rapidly recovered, and remained henceforth immune against further attacks. Smallpox inoculation had been practised in Turkey, China, and Elsewhere, but was first publicized in Northern Europe by Lady Mary Wortley Montagu, who had lived in constantinople (and who herself was seriously disfigured by smallpox). She persuaded the princess of Wales tohave two of her daughters inoculated in 1722. A trial was first made on six condemned prisoners in Newgate, on the understanding that if they survived they would be released. All six survived. As a result inoculation became increasingly widespread thereafter.
Inoculation against smallpox raises a number of delicate questions and, although it is easy for us to assume we know what the rightanswers to those questions were, contemporaries were right to find them difficult and perplexing. At one level the argument was straightforward. The chances of dying from inoculated smallpox were at first estimated at one in a hundred-in 1723 James Jurin, who was secretary to the Royal Society, and thus in a position to correspond with experts around the world, did a careful study which produced afigure of one in ninety-one. The chances of dying from normal smallpox were known to be around one in ten (excluding those who died under the age of 2). Most people were exposed to smallpox at some point. It therefore seemed to follow straighforwardly that inoculation would save large numbers of lives. John Arbuthnot, a mathematician and doctor, published in 1722 a statistical analysis that showedthat one in twelve deaths in London were due to smallpox, though he still preferred the claim that smallpox killed one in ten of the susceptible population on the grounds that many infants cheated smallpox by dying before it had a chance to infect them. (This line og argument was mistaken: Haygarth and percival would later show that one quarter of all smallpox fatalities were children under oneyear in age, and Arbuthnot had probably underestimated the proportion of Londoners dying of smallpox.) Similar but more complex calculations by James Jurin resulted in a more reliable figure of one in seven. Inoculation, it was argued, would save 1500 lives a year in London Alone. In England, despite a few vocal objectors, the case for inoculation was generally found persuasive.
In France, on theother hand, inoculation was rejecter by the medical establishment particularly the Paris Faculty of Medicine -- which continued to reject Harvey's theory of the circulation of the blood, along with one of the few effective drugs to be discovered in the Renaissance, chinchona, fom which quinine ( for the treatment of malaria) was later to be extracted. French doctors did not practise inoculation,and those in France who wanted to be inoculated had to turn either to laymen or to foreign doctors. Nevertheless, French intellectuals, such as Voltaire and La Condamine, urged their copatriots to copy the English. In 1760 La Condamine's friend Maupertuis persuaded the great swiss mathematician Daniel Bernoulli to enter the debate. Bernoulli set out to calculate the increase in averagate lifeexpectancy that would result from inoculation, and came up with the figure of two years.
In reply Jean d'Alembert questined whether most people were actually prepared to run a significant risk (say one in a hundred) of immediate death in order to gain only two years. The state and the society might gain if everyone was inoculated, but d'Alembert had considerable sympathy with cowardly individuals...