This is one of the letters in Voltaire's Letters on England (also known as Philosophical Letters), as translated by Leonard Tancock for the Penguin edition.
 It is whispered in Christian Europe that the English are mad and maniacs: mad because they give their children smallpox to prevent their getting it, and maniacs because they cheerfully communicate to their children a certain and terrible illness with the object of preventing an uncertain one. The English on their side say: “The other Europeans are cowardly and unnatural: cowardly in that they are afraid of giving a little pain to their children, and unnatural because they expose them to death from smallpox some time in the future.” To judge who is right in this dispute, here is the history of this famous inoculation which is spoken of with such horror outside England.
 From time immemorial the women of Circassia have been in the habit of giving smallpox to their children, even six months old, by making an incision in the arm and inserting into the incision a pustule that they have carefully removed from the body of another child. This pustule works in the arm where it is inserted like yeast in a piece of dough; it ferments and spreads its own qualities through the blood-stream. The spots of the child who has been given this artificial smallpox are used to carry the same disease to others. There is an almost continual circulation of it in Circassia, and when unfortunately there is no smallpox in the land people are as put out as they are elsewhere by a bad harvest.
 What introduced a custom into Circassia which seems so strange to other nations is however a cause common to the whole world: mother-love and self-interest.
 The Circassians are poor and their daughters are beautiful, and so they use them as their chief export. They supply beauties to the harems of the Grand Turk, the Sophy of Persia and those who are rich enough to buy and keep this precious merchandise.
 With the most honourable intentions they train these girls to perform dances full of lasciviousness and sensuousness, to rekindle by all the most voluptuous artifices the desires of the high and mighty masters for whom they are destined. These poor creatures go over their lesson with their mother every day, just as our little girls repeat their catechism, not understanding a word of it.
 Now it often happened that a father and mother, having taken a great deal of trouble to give their children a good upbringing, suddenly saw their hopes frustrated. Smallpox came into the family, one daughter died of it, another lost an eye, a third recovered but with a swollen nose, and the poor folk were ruined, with no resources. Often it even happened, when smallpox became epidemic, that trade was interrupted for several years, which caused a notable depletion in the seraglios of Persia and Turkey.
 A commercial nation is always very alive to its interests and neglects none of the knowledge that can be useful in its business. The Circassians noticed that out of a thousand persons, hardly a single one was attacked twice by serious smallpox, that certainly people can develop three or four slight attacks, but never two serious and dangerous ones, in a word that the true disease never occurs twice in a lifetime. Furthermore, they noticed that when smallpox attacks are very mild and the outbreak finds only a delicate and thin skin to pierce, it leaves no mark upon the face. From these natural observations they concluded that if a child of six months or a year had a mild attack it would not die and would not be marked, and would be immune from the disease for the rest of its days.
 To preserve the life and beauty of their children it only remained, then, to give them smallpox at an early age, and that is what they did by inserting into the child’s body a pustule taken from the most perfect and at the same time most favourable case of smallpox that could be found. The experiment was bound to succeed. The Turks, who are sensible people, soon adopted this custom, and today there is not a Pasha in Constantinople who does not give smallpox to his son and daughter as soon as they are weaned.
 Some people maintain that the Circassians originally took this custom from the Arabs, but we leave this historical point to be cleared up by some learned Benedictine, who will doubtless compose several folio volumes on the subject, with proofs. All I have to say on this matter is that at the beginning of the reign of George I, Lady Wortley Montagu, 13 one of the most intelligent women in England, and with a powerful intellect into the bargain, then living with her husband at the Embassy in Constantinople, decided without any hesitation to give smallpox to a child she had given birth to in that country. In vain did her chaplain point out that this procedure was not Christian and so could only succeed on infidels; Lady Wortley Montagu’s son thrived on it. Back in London this lady mentioned her experiment to the Princess of Wales, who is now Queen. It must be admitted that, titles and crowns apart, this Princess was born to encourage all the arts and do good to mankind. She is a delightful philosopher on the throne. She has never lost a chance of learning or of exercising her generosity. It was she who, hearing that a daughter of Milton was still alive and living in poverty, at once sent her a handsome present, she who is the patron of poor Father Courayer, she who deigned to mediate between Dr Clarke and Leibnitz. As soon as she heard about inoculation or insertion of smallpox, she tried it out on four criminals condemned to death. She saved their lives twice over, for not only did she snatch them from the gibbet but thanks to this artificial smallpox she prevented the natural death from it that they would probably have suffered later in their lives.
 Once assured of the practical success of this test, the Princess had her own children inoculated: England followed her example, and since then at least ten thousand children of good family thus owe their lives to the Queen and Lady Wortley Montagu, and as many girls are indebted to them for their beauty.
 Out of a hundred people in the world at least sixty have smallpox, and of these sixty, twenty die of it in the flower of their youth and twenty keep the unpleasant marks for ever. That makes one fifth of all human beings that this disease kills or permanently disfigures. Of all those inoculated in Turkey or England not one dies unless he is infirm and predisposed to die anyway, nobody is disfigured, nobody has smallpox a second time, assuming that the inoculation was properly done. So it is certain that if some French Ambassador’s wife had brought back this secret from Constantinople to Paris, she would have done the nation a lasting service. The Duc de Villequier, father of the present Due d’Aumont and one of the most balanced and healthiest men in France, would not have died in the prime of life.
 The Prince de Soubise, who enjoyed the most perfect health, would not have been carried off at twenty-five; Monseigneur, grandfather of Louis XV, would not have been buried in his fiftieth year; twenty thousand people who died in Paris in 1723 would still be alive. What! Aren’t the French fond of life? Do their women not care about their beauty? Indeed we are strange folk! Perhaps in ten years’ time we shall adopt this English method if the priests and doctors permit, or else in three months’ time the French will use inoculation because they fancy it, if the English get tired of it through fickleness.
 I understand that the Chinese have had this custom for a hundred years. The example of a nation that passes for the wisest and most strictly governed in the universe is a great thing in its favour. It is true that the Chinese set about it in a different way; they don’t make an incision but make the subject take in smallpox through the nose, like snuff. This is a more pleasant way, but it comes to the same thing and serves just as well to confirm that if inoculation had been practised in France the lives of thousands of people would have been saved.