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An Inquiry into the Causes and Effects of the Variolae Vaccinae [Literary Excerpt and Illustration]


Edward Jenner (1749-1823) was a physician in rural Gloucestershire. Like Lady Mary Wortley Montagu he learnt of a widely known folk remedy to protect against smallpox. Smallpox cases were increasing in the 18th century and had a mortality rate of 40%. At least 30% of those who survived were left horribly scarred. Smallpox was a disease of children and youth in particular. However, dairymaids and farmers believed that those who had contracted cowpox, a mild infection often found on the udders of cows, would not get smallpox. Jenner's interviews with local farmers led him to carry out a series of experiments using cowpox matter, or lymph (fluid), taken from the vesicles of cowpox on the hands of the dairymaid Sarah Nelmes. In May 1796 he inserted the lymph in the arm of a young boy called James Phipps who promptly came down with cowpox. In July Jenner inoculated Phipps with smallpox matter but he remained healthy and did not get the disease. Jenner carried out several of these experiments on villagers and the children of his servants before he published his findings. He called this new method of using cowpox to protect against smallpox, vaccination from vacca, the Latin word for cow. In fact historians now have evidence that local farmers had carried out this procedure before but Jenner was the first medical man to publish his findings on cowpox as a preventive remedy against smallpox in An Inquiry into the Cause and Effects of the Variolae Vaccinae, a Disease Discovered in Some of the Western Counties of England, Particularly Gloucestershire, and Known by the Name of the Cow-pox. Vaccination was not accepted quickly by all but it gradually became more popular as it was less risky than inoculation. The watercolor drawing shows the profound difference in the severity of infection caused by inoculation with smallpox as recommended by Lady Montagu versus vaccination with cowpox as recommended by Edward Jenner. Vaccination became compulsory in Britain in 1853.


Dr. Edward Jenner, "An Inquiry into the Causes and Effects of the Variolae Vaccinae," The Wellcome Library,; Edward Jenner, The Three Original Publications on Vaccination Against Smallpox, The Harvard Classics, 1909-14, (accessed October 13, 2008). Annotated by Lynda Payne.

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CASE XVI.—Sarah Nelmes, a dairymaid at a farmer's near this place, was infected with the cow-pox from her master's cows in May, 1796. She received the infection on a part of her hand which had been previously in a slight degree injured by a scratch from a thorn. A large pustulous sore and the usual symptoms accompanying the disease were produced in consequence. The pustule was so expressive of the true character of the cow-pox, as it commonly appears upon the hand, that I have given a representation of it in the annexed plate. [In original.] The two small pustules on the wrists arose also from the application of the virus to some minute abrasions of the cuticle, but the livid tint, if they ever had any, was not conspicuous at the time I saw the patient. The pustule on the forefinger shews the disease in an earlier stage. It did not actually appear on the hand of this young woman, but was taken from that of another, and is annexed for the purpose of representing the malady after it has newly appeared.


CASE XVII.—The more accurately to observe the progress of the infection I selected a healthy boy, about eight years old, for the purpose of inoculation for the cow-pox. The matter was taken from a sore on the hand of a dairymaid, 10 who was infected by her master's cows, and it was inserted, on the 14th of May, 1796, into the arm of the boy by means of two superficial incisions, barely penetrating the cutis, each about half an inch long.


On the seventh day he complained of uneasiness in the axilla, and on the ninth he became a little chilly, lost his appetite, and had a slight headache. During the whole of this day he was perceptibly indisposed, and spent the night with some degree of restlessness, but on the day following he was perfectly well.


The appearance of the incisions in their progress to a state of maturation were much the same as when produced in a similar manner by variolous matter. The only difference which I perceived was in the state of the limpid fluid arising from the action of the virus, which assumed rather a darker hue, and in that of the efflorescence spreading round the incisions, which had more of an erysipelatous look than we commonly perceive when variolous matter has been made use of in the same manner; but the whole died away (leaving on the inoculated parts scabs and subsequent eschars) without giving me or my patient the least trouble.


In order to ascertain whether the boy, after feeling so slight an affection of the system from the cow-pox virus, was secure from the contagion of the smallpox, he was inoculated the 1st of July following with variolous matter, immediately taken from a pustule. Several slight punctures and incisions were made on both his arms, and the matter was carefully inserted, but no disease followed. The same appearances were observable on the arms as we commonly see when a patient has had variolous matter applied, after having either the cow-pox or smallpox. Several months afterwards he was again inoculated with variolous matter, but no sensible effect was produced on the constitution.CASE XVIII.—John Baker, a child of five years old, was inoculated March 16, 1798, with matter taken from a pustule on the hand of Thomas Virgoe, one of the servants who had been infected from the mare's heels. He became ill on the sixth day with symptoms similar to those excited by cow-pox matter. On the eighth day he was free from indisposition.


There was some variation in the appearance of the pustule on the arm. Although it somewhat resembled a smallpox pustule, yet its similitude was not so conspicuous as when excited by matter from the nipple of the cow, or when the matter has passed from thence through the medium of the human subject.


This experiment was made to ascertain the progress and subsequent effects of the disease when thus propagated. We have seen that the virus from the horse, when it proves infectious to the human subject, is not to be relied upon as rendering the system secure from variolous infection, but that the matter produced by it upon the nipple of the cow is perfectly so. Whether its passing from the horse through the human constitution, as in the present instance, will produce a similar effect, remains to be decided. This would now have been effected, but the boy was rendered unfit for inoculation from having felt the effects of a contagious fever in a workhouse soon after this experiment was made.


CASE XIX.—William Summers, a child of five years and a half old, was inoculated the same day with Baker, with matter taken from the nipples of one of the infected cows, at the farm alluded to. He became indisposed on the sixth day, vomited once, and felt the usual slight symptoms till the eighth day, when he appeared perfectly well. The progress of the pustule, formed by the infection of the virus, was similar to that noticed in Case XVII, with this exception, its being free from the livid tint observed in that instance.


CASE XX.—From William Summers the disease was transferred to William Pead, a boy of eight years old, who was inoculated March 28th. On the sixth day he complained of pain in the axilla, and on the seventh was affected with the common symptoms of a patient sickening with the smallpox from inoculation, which did not terminate till the third day after the seizure. So perfect was the similarity to the variolous fever that I was induced to examine the skin, conceiving there might have been some eruptions, but none appeared. The efflorescent blush around the part punctured in the boy's arm was so truly characteristic of that which appears on variolous inoculation that I have given a representation of it. [In original.] The drawing was made when the pustule was beginning to die away and the areola retiring from the centre.

How to Cite This Source

Dr. Edward Jenner, "An Inquiry into the Causes and Effects of the Variolae Vaccinae [Literary Excerpt and Illustration]," in Children and Youth in History, Item #165, (accessed August 10, 2021). Annotated by Lynda Payne