VACCINATION is a process of transmit ting by inoculation a specific disease known as vaccima, cowpox, or modified smallpox from one•susceptible reagent to another —either from animal to animal, from animal to man, or from man to man. Nearly all the warm-blooded animals are susceptible to vaccinia, but they may vary considerably in such susceptibility; in some it is slight, only affecting a certain tissue, as the cornea; while in others it may affect the cornea, skin and mucous membranes. The term vaccination also is used in a broader sense, and is made to apply to other diseases than vaccinia. It may denote the process by which other dis ease-producing agents are inoculated into a sus ceptible species in such a way as to render it refractory to a given disease contracted in the natural way. The sole purpose at the present time in inoculating vaccinia into a susceptible reagent is for the purpose, primarily, of render ing it insusceptible to the disease smallpox, and the propagation, continuation and multiplica tion of the specific material.
properly appreciate the subject of vaccination and its beneficent effects in the suppression and control of the much-dreaded disease, smallpox, it will be necessary to review briefly some few incidents of its early history. Credit is due to Edward Jenner (q.v.), a phy sician living in the western part of England, for its discoVery and application. The subject of the protective effect of vaccination contracted by persons who had been milking cows which were suffering from an eruptive disease, known then as cowpox, attracted Jenner's attention even when a pupil. On the completion of his med ical studies and return to Berkeley, the idea was ever dominant in his mind; and as soon as op portunity offered, he began to make his obser vations and investigations of cowpox. But facts which were so convincing to his own mind he evidently feared as unacceptable to his medical brethren, and so he made his ideas known to only his friend Gardner, to whom he writes: aI have entrusted a most important matter to you, which I firmly believe will prove of essential benefit to the human race. I know you, and should not wish that what I have stated he brought into conversation; but should anything untoward turn up in my experiments, I should be made, particularly by my medical brothers, the subject of ridicule." In 1788 he brought his
observations and theory before the medical pro fession, but did not make any impression, save in one instance. A colleague, acting upon Jen ner's suggestion soon after its announcement, inoculated a child with cowpox matter and afterward with smallpox virus. It did not have the smallpox. For the next eight years Jen ner was patiently pursuing his observations, col lecting data regarding cowpox and its transmis sibility to persons, an l particularly notiii_ its protective effects of must smallpox. In day 1796, he issued his celebrated treatise entitled 'An Enquiry into the Causes and Effects of the Varioke Vaccines, a I )i Diqcoverca in Some of the Westein LonilLICS Particularly Gloucestershire, and Known by the Name of Cowpox.' It attracted no little at tention. The majority of the medical profes sion, and many of the intelligent laity, appeared now to be ready to accept his conclusions, and eager to apply his method. His position was, however, not an enviable one. True, letters came from all parts of the world asking infor mation about his discovery, how the material could be obtained, etc., to which he willingly and readily responded so far as he was able. On the other hand, notwithstanding its ready acceptance, he was beset with troubles. There were not a few medical men who were un willing to accept his discovery, and assailed him in every possible way by misstatements, mis representations and abuse. These he attempted to answer in a spirit of fairness and honesty. Later on, when the practice of vaccination be came more general, his labors as °a vaccine clerk to the world," as he terms it, became less and less burdensome. He had the satisfaction of seeing his method adopted in nearly every civilized country. There were many, notwith standing, who were loath, as some are even now, to abandon their fixed opinions as to its efficacy and resisted to the last.