Edward, the third son of the Rev. Stephen Jenner, was born May 17, 1749, in the vicarage-house of Berkeley in Gloucestershire, of which parish his father, a man of independent fortune, and of a family long established and esteemed in that neighbourhood, was incumbent. At the death of that parent in 1754, the care of Edward Jenner’s education devolved upon his eldest brother, Stephen, who succeeded to the living of Berkeley, and faithfully and affectionately discharged the duties of a father towards him.

He began at a very early age to give tokens of that fondness and aptitude for the study of natural history, which first directed the choice of his profession; and afterwards led him, by steps which may be easily traced, to the discovery of a method of securing the constitution against the small-pox, by a remedy so mild as to be scarcely an inconvenience, yet so effectual as almost to have extinguished that disease in some countries where it has been energetically used.

Having finished his school education and fixed upon a profession, Jenner was apprenticed at the usual age to Mr. Ludlow, a surgeon practising at Sodbury near Bristol; and in 1770, when nearly twenty-one, he came to London, and put himself under the tuition of John Hunter, in whose house he lived for two years, as much in the capacity of a friend as in that of a pupil, with great advantage to his professional studies. The intimacy between these two eminent men was very close and cordial, and subsisted till Hunter’s sudden death in 1793. It is attested by many letters from Mr. Hunter, which Jenner carefully preserved; his own were probably destroyed with the rest of Hunter’s papers by the late Sir Everard Home. Their correspondence relates chiefly to facts and experiments in natural history.

The success with which Jenner had already pursued his studies, and the respect entertained for his talents by his illustrious instructor at a period when their intercourse was yet in its infancy, may be gathered from his being selected in 1771, on the recommendation of Mr. Hunter, to arrange the collections in natural history which had been made by Sir Joseph Banks in his voyage round the world with Captain Cook, then just completed. Jenner acquitted himself so well of this charge, that he was offered, though little more than twenty-two years of age, the situation of naturalist to the second expedition under the command of Captain Cook, which sailed in 1772. This was a flattering proposal to so young a man, and consonant to Jenner’s ruling tastes; nevertheless he declined it. It is fortunate for mankind that he chose the laborious seclusion of a country practice in preference to aiming at distinction and wealth; for in no other sphere could he have found opportunities of pursuing his discovery of vaccination through all the perplexities in which his early researches into that subject involved him. Indeed, it is probable that considerations of this kind, independently of his fondness for a country life, had their weight with him in the choice; for the idea had already taken strong hold of his naturally sanguine feelings and quick apprehension, that he was furnished with a clue which might lead him to a result of the highest importance to mankind.

It may be added here that a few years after this time he declined a very lucrative situation in India, as well as a much more tempting proposal from Mr. Hunter, in 1775, to join him in a project for establishing in London a school of natural history, including medicine, of which Jenner was to undertake the anatomical department.

Having determined to settle in the country, and being amply provided with the requisite knowledge, Jenner established himself as a general practitioner at Berkeley. Here he speedily acquired a profitable and extensive practice; so much so, indeed, that finding his health giving way, he was obliged to limit himself to the practice of medicine alone; for which purpose he purchased, as it was then customary, the degree of doctor at St. Andrew’s in 1792.

But he not only attained at an early age to a high degree of professional reputation, but won the affectionate esteem of all with whom he associated. It is related of him that his friends were in the habit of joining in his daily professional rides, often of considerable extent, for the sake of his agreeable and instructive conversation; and that when any of them were ill, he would sometimes make their houses the head-quarters of his practice for the time being, and remain in close attendance upon them till their recovery.

Music, the lighter kinds of literature, both as a reader and occasionally as an author, and the innocent recreations of society, which no one enjoyed more keenly than himself, were the means by which Jenner lightened the burden of his professional labours; but his chief amusement was natural history, including geology, a science then in its infancy, for the study of which his position in the vale of Gloucester afforded ample opportunity, the neighbourhood abounding with fossil remains, and exhibiting a great variety of terrestrial structure. Towards subjects of this nature he was led, not only by his original bias, but by his correspondence with Hunter, Banks, and Parry.

In 1778 he formed a medical society, which held its periodical meetings at Rodborough, for the purpose of communicating professional information and promoting a friendly feeling among the members. In furtherance of these objects, Jenner contributed several important and original papers, the substance of which is now embodied in medical science, without his property in them being generally known. Among these were essays on the nature and causes of Angina Pectoris, on a peculiar disease of the heart occurring in acute rheumatism, and on several of the more severe affections of the eye. He also belonged to another medical society, meeting at Alveston near Bristol, to the members of which, who were men of congenial dispositions with his own, he was personally much attached. Upon one topic, however, they did not agree; for it is said that he was in the habit of enlarging so frequently upon his favourite speculation of the cow-pox, that the subject was at length proscribed, and he was jestingly forbidden to renew it on pain of expulsion. This club was for many years a source of much enjoyment and advantage to him, and we may suppose that he was a very principal contributor to the diversion of the other members; for it ceased to exist in 1789, when other objects began to engross the time that he could spare from his practice. In March of the previous year, at the age of thirty-seven, he married Miss Catharine Kingscote, by whom he had several children. The choice appears to have been a very fortunate one for his domestic happiness.

In 1786 he had communicated to Mr. Hunter, in the form of an essay, the result of several years’ careful observation of the singular habits of the cuckoo, till then a mystery to naturalists. It was presented by Mr. Hunter to the Royal Society, and was printed entire in their Transactions in 1789, having been returned to Jenner in the mean time, in order that he might record some additional facts which he had ascertained. This tract has been considered as a very masterly performance, and was the occasion of the author being elected to the fellowship of the Royal Society. It is not a little remarkable that Mr. Hunter, like Jenner’s friends at Alveston, thought so doubtfully of his views on the subject of vaccination, that he cautioned him against publishing them, lest they should interfere with the fame he had acquired in the learned world by his ‘Essay on the Cuckoo.’ But the event proved that the caution, though well meant, was unnecessary. Jenner was not more disposed than his gifted master to admit any conclusion on merely collateral grounds, that might be put to the test of experiment. This, however, was too new and important a matter to be lightly or prematurely hazarded; and Jenner waited long and patiently for an opportunity of thus testing his opinions, losing in the mean time no occasion of collecting additional information. The idea, thus watchfully and laboriously improved, was first excited in his mind while he was an apprentice at Sodbury, by a remark accidentally dropped by a young countrywoman in his master’s surgery, who, overhearing a conversation about the small-pox, observed that she had no fear of catching that disease as she had taken the cow-pox. Jenner, who was always alive to any subject connected with natural history, was induced to make more particular inquiries into this complaint, of which he had never heard before; and the answers he received were such as to suggest the probability of substituting it with advantage for the inoculated small-pox. Of this theory he never lost sight till he established it on the clearest evidence, and with it his unrivalled claim to the perpetual gratitude of mankind.

The cow-pox is a disease of the eruptive kind, which is sometimes extensively prevalent among cattle in large dairy countries where they are herded together in numbers, but often disappears for a long time together. Though commonly mild, it is occasionally so severe as to terminate fatally; and it is believed, on strong grounds, to have been at different times even pestilential among them, and as such, to have been mentioned by various writers on rural economy, ancient and modern, as well as in medical and other histories. It is generally, however, a very mild disorder, appearing on the udder of the cow, at first in the form of vesicles much resembling those of small-pox; and it is sometimes, as in the instance which first attracted the attention of Jenner, communicated to the hands of milkers. In such cases, an eruption of similar vesicles takes place on the hands and arms, not without much swelling and inflammation, and occasionally with fever and disturbance of the health for some days. It has never been known to prove fatal when thus communicated, or to have left any unpleasant effects behind it, except a few indented marks in the situation occupied by the pustules. It is not communicable, like small-pox in the human subject, by the effluvia; but the matter, or lymph as it is called, contained in the vesicles, must be actually inserted under the skin, or applied to a raw or an absorbing surface. But the most important of its peculiarities is the security it affords against the infection of small-pox. This property was well known among the agricultural classes in the grazing districts before the time of Jenner, and it has been stated that individuals among them had turned their knowledge of it to account for the protection of their families, by inoculating them with the vaccine disease. But this circumstance, alleged on very scanty evidence by those who were opposed to Jenner’s claims, cannot lessen the merit of his independent discovery, of which each step was communicated in succession to a numerous circle of medical friends, and is recorded in the most authentic form. His reputation is, on the other hand, enhanced by the fact that, although the immunity conferred by the casual disease in milkers had frequently come under the notice of medical men from their failing in such persons to produce the small-pox by inoculation, yet the idea of introducing the disease of an animal into the human frame was so little in consonance with any former practice, that Jenner was the first among his brethren to conjecture that cow-pox, as the milder disease, might advantageously supersede the inoculated small-pox; and that, as the latter is rendered less virulent by inoculation, so the former introduced in the same way might be milder than the casual complaint, and yet retain its protecting power. He had even communicated this conjecture to Hunter, himself no mean innovator in medicine, so early as the year 1770; and Mr. Hunter was for many years in the habit of mentioning it in his public lectures coupled with Jenner’s name: but the proposed substitution was so distasteful, or appeared of such questionable propriety, that it obtained no favourable notice till it was forced by the inventor on the public attention, thirty years after it had first attracted his own.

It would be interesting to enter into a detail of the progress of Jenner’s discovery and of its introduction into general use, as well as to show its inestimable value to society by a reference to statistical facts. This, however, can only be done here in a very cursory manner.

The way in which the idea was first suggested to him has been already mentioned. After his return to Berkeley from London, he pursued the subject with great patience and sagacity for many years. In the course of these preliminary inquiries he found reason to believe that of several kinds of vesicular disease in the cow, but one had the property of securing from the small-pox, and that one exclusively, or at least with the greatest certainty, in its first stage. He also ascertained that the horse is subject to an eruption of similar vesicles, apparently arising without infection, and popularly known by the name of the grease. The matter issuing from these is sometimes conveyed to the cow by milkers engaged in farriery; and Jenner conceived it to be the original and only source of cow-pox among the herds. The opinion is not generally held at present to its full extent; but experiments by himself and others since the publication of his Inquiry have proved a fact much disputed at the time, that he was right in believing the diseases to be identical, whatever may be their origin.

It may be mentioned as a curious circumstance, that the first lymph transmitted in an active state to British India in 1802 by Dr. De Carro of Vienna, long the only source of vaccination in that country, had been furnished to him by Dr. Sacco of Milan, from genuine vesicles produced by direct inoculation from the horse, without passing through the cow; an intervention which, till about that period, Jenner had continued to think essential to the production of the true disease in man.

In addition to these and other curious results, laboriously collected during a period of twenty-six years, Dr. Jenner at length arrived at a rational conviction of the safety of the experiment he meditated, from observing the invariable harmlessness of the disease when casually taken: he determined therefore to put his long-cherished idea to the trial on the first opportunity.

This offered on the 14th of May, 1796, the anniversary of which is still kept as a festival at Berlin. On that day he inoculated a boy of the name of Phipps in the arm, from a pustule on the hand of a young woman who was infected by her master’s cows. The boy went favourably through the disease. On the 1st of July he was inoculated for the small-pox, and, as Jenner had predicted, without effect.

The feelings of the sanguine philanthropist may be conceived. They cannot be better described than they have been by himself in the following terms. “While the vaccine discovery was progressive, the joy I felt at the prospect before me of being the instrument destined to take away from the world one of its greatest calamities, blended with the fond hope of enjoying independence and domestic peace and happiness, was often so excessive, that in pursuing my favourite subject among the meadows, I have sometimes found myself in a reverie. It is pleasant to me to recollect that these reflections always ended in devout acknowledgments to that Being from whom this and all other mercies flow.”

During the next two years many other equally successful trials were made; and at length the discovery was published to the world in June, 1798, in a quarto pamphlet of seventy pages, which had been previously subjected to the most rigorous criticism and revision by a few chosen friends who met for that purpose at the house of Thomas Westfaling, Esq., at Rudhall, near Ross. It is entitled ‘An Inquiry into the Causes and Effects of the VariolÆ VaccinÆ; a disease discovered in some of the Western Counties of England, particularly Gloucestershire, and known by the name of the Cow-pox.’ The pamphlet is enriched with the detail of sixteen cases of the casual, and seven of the inoculated disease, the latter including the case of one of the author’s sons; and with coloured drawings of the appearances in both.

The style of this pamphlet, as well as of others which succeeded it from Jenner’s pen in the course of a few years, is remarkably modest, and admirable in all respects, which probably contributed much to the early favour it received. The facts were such as to defy contradiction, and the conclusions so just and mature, that the experience of nearly forty years has been able to add little more than its seal of confirmation to them. The few errors that have been detected relate chiefly to the degree of protection afforded by the cow-pox, which Jenner affirmed to be perfect: it is now however believed to be incomplete, perhaps in three instances out of every hundred; that small proportionate number passing, in general after the lapse of some years, through a very mild and modified small-pox, in which the per-centage of fatal cases is certainly not more, and probably much less, than five; being not more than three in 2000 of all vaccinated persons, while the rate of mortality even in inoculated small-pox is one in fifty, or forty in 2000. It should be borne in mind that small-pox itself sometimes occurs a second time even in a severe and fatal form, as in the case of Louis XV. Some constitutional peculiarity is probably the occasion of both these anomalies; and this supposition will also account for the often-observed fact, that small-pox after vaccination commonly affects several members of the same family almost simultaneously, thus giving an appearance of failure in a proportion much greater than the truth.

Another position advanced by Jenner in this pamphlet is too remarkable to be passed over. After stating his belief that the cow-pox originates from the horse in the way already mentioned, he proceeds to suggest that the small-pox may have been itself originally morbid matter of the same kind, aggravated into a malignant and contagious form by accidental circumstances. But this opinion, though plausible, is not considered by any means as established.

Favourably as his work was received, the author, who had come to London partly to superintend the publication, was unable to obtain an opportunity of displaying the disease in that city, which had been the chief object of his visit; and returned, much disappointed, to Cheltenham, where he now frequently resided, in the middle of July. He left, however, some vaccine lymph with Mr. Cline, who was the first surgeon in London that ventured to make a trial of it. The complete success of the experiment, which was publicly performed, so strongly interested the profession, that the new practice became quickly popular, in spite of a warm though partial opposition, which was put down in the summer of 1799 by a manifesto expressive of confidence in its efficacy and safety, signed by seventy-three of the most eminent medical men in the metropolis. In the same year some unfortunate occurrences took place in consequence of Dr. Woodville, the physician of the Small-pox Hospital, having incautiously used and distributed matter from persons whom he had inoculated with small-pox a few days after vaccination, before it had taken a sufficient hold. The mongrel lymph thus produced sometimes occasioned one, sometimes the other disease; their effects were confounded; and some deaths which ensued, as well as a general eruption of the skin which took place in many instances, were attributed to the cow-pox. This and other mistakes would probably have much retarded the general adoption of vaccination, but for the promptitude of Jenner to discover and expose the source of the error.

In 1802 a parliamentary inquiry into the value of the new method of preventing small-pox, including Jenner’s claim to the discovery of it, was instituted, and a grant was voted to him of 10,000l. In 1807 he received an additional vote of 20,000l., which, considering that he had been the instrument of saving in England alone at least 45,000 lives annually, will seem by no means an extravagant mark of national gratitude and respect.

In 1803 the Royal Jennerian Society, for the encouragement of vaccination, was established in London under the superintendence of Dr. Jenner. In 1808 this society was merged by his advice in the National Vaccine Establishment, which still continues to dispense the blessings of the antidote at the public charge.

The growing interest in the public mind in favour of vaccination was of course everywhere extended to its author, who, in spite of several unworthy cabals, and attempts to deprive him of the credit of a discovery peculiarly his own, was received among all ranks with the highest distinction at home, and also gratified with various continental honours. If he had thought fit to settle in London, he might undoubtedly have secured wealth in proportion to his reputation; but he preferred the quiet enjoyment of rural life and domestic happiness. His death took place at Berkeley, from a sudden attack of apoplexy, in February, 1823, in the seventy-fourth year of his age. The latter years of his life were spent between Berkeley and Cheltenham, and in occasional visits to London, in the zealous prosecution of his favourite subjects of research, and successful endeavours to diffuse the blessings of his discovery more widely in his own and other lands.

In England, however, these have not been so extensively felt as in some other countries where the form of government has given facilities for the enforcement of vaccination. The small-pox consequently prevails to a considerable extent in this country, and especially in London. Yet the annual number of deaths from small-pox within the bills of mortality is at present under 700; the largest number in one year since the general practice of vaccination having been 1299, in 1825. A century ago, when the population certainly did not reach half its present amount, the yearly average was 2000, the maximum being in 1796, when the mortality swelled to 3549. That this decrease is wholly due to vaccination cannot be doubted; the advantage, however, is partly indirect, and has arisen from the discontinuance of the practice of inoculating for the small-pox, which afforded security to individuals, but increased the general mortality by keeping alive a constant source of infection. But the most striking examples of the advantage derived from vaccination are to be found on the continent. Thus at Berlin, where the average annual amount of deaths from small-pox was 472 for the twenty years previous to 1802, and 1646 died in 1801, the mortality so speedily diminished after the enforcement of vaccination by law, that in 1821 and 1822 there was only one death in each year. These and similar instances which might be adduced from other countries, seem almost to warrant us in adopting the sanguine expectation of Jenner, that by means of his discovery this disgusting and dreadful malady, from which not four in a hundred of the human race wholly escaped, and which destroyed a tenth part of all that were born, and disfigured where it did not destroy, may yet be swept from the face of the earth.

The best books of reference on the subjects of this memoir are ‘Baron’s Life of Jenner,’ ‘Moore’s History of the Cow-pox,’ Dr. Gregory’s admirable articles in the ‘EncyclopÆdia of Medicine,’ and the reports of various parliamentary committees, especially those of 1802 and 1833.