Here we are behind the scenes at a great discovery; "as I ventured to predict"; prediction is part of scientific theorizing; there is a place for legitimate prediction as there is for experimentation. All discoverers have made predictions; Harvey predicted the existence of the capillaries, Halley predicted the return of his comet, Adams predicted the place of the planet Neptune, the missing link in the evolutionary series of the fossil horses had been predicted long before it was actually found by Professor Marsh. Pasteur predicted that the sheep inoculated with the weak anthrax virus would be alive in the anthrax-infected field, while those not so protected would all be dead. A prediction verified is a conclusion corroborated, an investigator encouraged.

Early in 1797, through another outbreak of cowpox, Jenner was able to inoculate three persons with variola, only to find as before that they were immune from smallpox. He now felt himself justified in preparing a paper for the Royal Society, the highest scientific tribunal in England. The council, however, returned him his paper with the remark that in their opinion the amount of evidence was not strong enough to warrant its publication in the Transactions. Jenner was wise enough not to be discouraged, and so in June, 1798, he published the paper himself under the title, "Inquiry into the causes and effects of the Variolae-Vacciniae, a disease discovered in some of the western counties of England, particularly Gloucestershire, and known by the name of cowpox." This historic pamphlet, which ranks with the great classics of medicine, was dedicated to Dr. O. H. Parry, of Bath. Later on the Royal Society was sagacious enough to elect the very man whose paper it had previously refused.

While in London attending to the publication of his pamphlet, Dr. Jenner called on the great surgeon Mr. Cline, and left some cowpox virus with him for trial. Cline inoculated a young tubercular patient with vaccinia and later with smallpox in no less than three places. In due time this patient did not show a sign of smallpox. So impressed was Cline with this remarkable result that he wrote to Jenner thus: "I think the substitution of cowpox poison for smallpox one of the greatest improvements that has ever been made in medicine. The more I think on the subject, the more I am impressed with its importance."

The word "vaccination" was coined by the French, so remarkable for the aptness of their descriptive terms, and it has ever since remained with us as a convenient expression for the inoculation of vaccinia as protecting from variola.[4]

[4] It is certainly not necessary to point out that the principle of vaccination has been one of wide application in modern medicine. Our word "vaccine" testifies to this. A vaccine is a liquid, the result of bacterial growth, injected into a patient in order to render him immune from that particular disease which is caused by sufficient infection with the microorganisms in question, e. g., of typhoid fever or of plague.

Dr. Jenner's views were now becoming known, and the critics and the doubters had appeared: St. Thomas has always had a large following. The most formidable of the early objectors was Dr. Igenhouz, who had come to London to study inoculation for variola, and had already inoculated, among other notable persons, the Archduchess Theresa Elizabeth of Vienna. The careless vaccinations of Doctors Pearson and Woodville at the London Smallpox Hospital brought much apparent discredit on Jenner's work. In all his early work Jenner used lymph obtained directly from papules on the cow or calf, but Woodville in 1799 showed that excellent results could be got from arm-to-arm vaccination. As this latter method is a very convenient one, the technique was widely adopted. We have to remember that we are speaking of a period about sixty years before Lister gave to suffering humanity that other great gift, antisepsis: and so many arms "went wrong," not because of being vaccinated, but because the scratches were afterwards infected by the microorganisms of dirt. Jenner knew well the difference between the reaction of clean vaccination and that of an infected arm, but a great many medical men of his time did not, and so he was constantly plagued with reports of vaccinations "going wrong" when it was septic infection of uncleansed skin that had occurred. The explanation of these things by letter consumed a very great deal of his valuable time. By the end of 1799 a large number of persons had, however, been successfully vaccinated. As one Pearson proved troublesome by starting an institution for public vaccination on principles which Jenner knew to be wrong, and as Jenner found himself virtually supplanted and misrepresented, he came up to London in 1800 to vindicate his position. The King, the Queen and the Prince of Wales, to whom he was presented, materially helped on the cause by countenancing the practice of vaccination. Lord Berkeley, his Lord of the Manor, was in this as in all things a kind and wise patron. In the United States of America vaccination made rapid progress, having been introduced there under the good auspices of Dr. Waterhouse, professor of medicine at Cambridge, Mass. The discovery was announced with true American informality as "Something curious in the medical line," on March 12, 1799.

Things went even better on the continent of Europe; deCarro, of Vienna, inaugurated vaccination with such zeal and discrimination that it spread to Switzerland, France, Italy and Spain. From Spain it passed over to Latin America. In Sicily and Naples, "the blessed vaccine" was received by religious processions. Sacco, of Milan, commenced vaccinating in 1801, and in a few years had vaccinated 20,000. In Paris, a Vaccine Institute was established; and Napoleon ordered all his soldiers who had not had smallpox to be vaccinated. On Jenner's application, the Emperor liberated several English prisoners remarking—"What that man asks is not to be refused." Napoleon voted 100,000 francs for the propagation of vaccination. Lord Elgin introduced it into Turkey and Greece. The Empress of Russia, Catherine II., was one of the greatest supporters of Jennerian vaccination. She decreed that the first child vaccinated in Russia should be called "Vaccinoff," should be conveyed to Petrograd in an imperial coach, educated at the expense of the state and receive a pension for life. The Emperor of Austria and the King of Spain released English prisoners at Jenner's request. There were statues of Jenner erected abroad, at Boulogne and at Brunn, in Moravia, before any in England. Thus the European countries showed their gratitude to the Englishman whose patience, genius and absence of self-seeking had rid them of the detestable world-plague of smallpox. Vaccination was made compulsory by law in no less than five European countries before it was so in the United Kingdom in 1853. In eight countries vaccination is provided free at the expense of the government. The clergy of Geneva and of Holland from their pulpits recommended their people to be vaccinated. In Germany, Jenner's birthday (May 17) was celebrated as a holiday. Within six years, Jenner's gift to humanity had been accepted with that readiness with which the drowning clutch at straws. The most diverse climes, races, tongues and religions were united in blessing vaccination and its discoverer. The North American Indians forwarded to Dr. Jenner a quaintly worded address full of the deepest gratitude for what he had saved them from: "We shall not fail," said these simple people, "to teach our children to speak the name of Jenner, and to thank the Great Spirit for bestowing upon him so much wisdom and so much benevolence."

There are two allusions to smallpox in "Don Juan," which was published in 1819, showing to what an extent Jennerian teachings were in the air. The first is:

The doctor paid off an old pox
By borrowing a new one from an ox.
(Canto I., stanza 129.)

The second is: