There is no doubt that Jenner's medical contemporaries, at least in England, failed to appreciate the magnitude of the gift their colleague had presented not merely to his own country, but to the world at large. The discovery had, of course, been led up to by several different lines of indication, but this in no way detracts from the genius of Jenner in drawing his memorable inductions from the few facts which others had known before his time. The fame of Newton is no whit diminished because Copernicus, Kepler and Galileo lived and worked before him, the credit due to Harvey is none the less because many before his time had worked on the problem of the heart and vessels, and because some of them, notably Cesalpinus, came within a very little of the discovery of the circulation; the achievements of Darwin are not to be belittled because Lamarck, Malthus or Monboddo had notions in accordance with the tenor of his great generalization of evolution among living beings. Certainly Jenner had precursors; but it was his genius and his genius alone which, putting together the various fragments of knowledge already possessed, gave us the grand but simple induction based on his own experiments that vaccinia prevents from variola. It was too simple and too new to be appreciated in all its bearings either by the medical men or the laity of his own day. Its impressiveness is not inherent in it, as it is in the mathematical demonstration of universal gravitation, as it is in the atomic theory or in that of the survival of the fittest through natural selection. The English country doctor merely said in essence—"let me give you cowpox and you will not get smallpox." Unless the fact of this immunity is regarded as possessed by all the nations of the world for ever more there is nothing particularly impressive in it; and so it failed to impress his contemporaries. It is only when we contrast the loathsomeness and danger of smallpox with the mildness and safety of vaccinia and varioloid that we grasp the greatness of the work which Jenner did for mankind. The very simplicity of vaccination detracts from its impressiveness unless its results are viewed through the vista of the centuries. We need the proper historical perspective in this as in all else. Thus viewed, however, the simplicity of the procedure and the universality of its application are most imposing. Vaccination does not, indeed, dazzle the scientific imagination like some of the other generalizations of biology, but it is one that has been gloriously vindicated by the subsequent history of the world's hygiene.
Jenner knew himself to be a benefactor of the human race; he would have been insincere if he had pretended otherwise; he finished his first paper with these words: "I shall endeavor still farther to prosecute this enquiry, an enquiry, I trust, not merely speculative, but of sufficient moment to inspire the pleasing hope of its becoming essentially useful to mankind"; and on his death-bed he said, "I do not marvel that men are not grateful to me, but I am surprised that they do not feel grateful to God for making me a medium of good."
In private life Dr. Jenner was amiable and kind-hearted. Dibden said of him: "I never knew a man of simpler mind or of warmer heart." He was particularly kind to the poor. Dr. Matthew Baillie said of him: "Jenner might have been immensely rich if he had not published his discovery."
We may in conclusion examine some of the objections to and criticisms of vaccination. The objections can be classified as those entertained (a) by medical men and (b) those by the public generally.
The objections raised by medical men are now a matter of ancient history. Each generation of medical men has refused at first to admit any new teaching promulgated in its time; physiological inertia is not at once overcome. The most enlightened of Jenner's critics did really believe that he was drawing too extensive an induction from insufficient data; this was the position of the Royal Society in 1788; but the Edinburgh reviewer of 1822 should have known better. The purely technical criticisms of Jenner's work have by this time been fully assessed and replied to. It is true that at one time it was not clear what were the relationships of chickenpox and smallpox, of vaccinia and variola, of vaccinia and varioloid, of the various forms of pox in animals—cowpox, swinepox, horsepox or grease—either inter se or to human smallpox. But I do not suppose that in this year of grace 1914 there can be found one properly trained medical man, acquainted with the history of Jennerian vaccination, familiar with the ravages of smallpox and with the protective power of vaccinia, who could be induced, by no matter how large a bribe, to say that he disapproved of vaccination or that he believed it did not protect from smallpox. There are cranks in all walks of life, but the medical crank who is also an anti-vaccinationist is happily the rarest of them all.
The lay objectors—the professed anti-vaccinators—are with us yet in spite of some very serious lessons which have been taught them. We may pass by the objectors of the class who believe that vaccinated persons cough like cows and bellow like bulls; these objections go into the limbo of old wives' fables or into the category of wilful misrepresentation. Unfortunately there is a large class of persons who can believe the absurdest nonsense about any subject which is particularly distasteful to them.[6] Another class of objection is the sentimental repugnance to the idea of being given one of the diseases of "the lower animals." Now the fact is that already we share a great many diseases with the lower animals, a few of them being tuberculosis, anthrax, rabies, tetanus, cancer, pleuro-pneumonia, certain insect-borne diseases, some parasitic worm diseases and some skin diseases like favus. As the knowledge of the lowly origin of many of our diseases is more widespread, this sort of objection will die out.
[6] Antivaccinators constantly allude to calf-lymph as "filth"; if lymph is filth, then I am able to assure them that each one of them has about three liters of it in his own body.
An objection which is worthy of more consideration is that in being vaccinated a child is apt to contract some infectious disease such as tuberculosis or syphilis which are the two most dreaded. Now so long as arm-to-arm vaccination was the routine practice, there was a remote probability that this sort of accident might occur. It appears to be true that a few accidents of this kind have occurred, just as a few arms have become septic or had erysipelas develop in them. But when the few such cases are compared with the millions and millions of uncomplicated vaccinations, their importance becomes very insignificant. Now that arm-to-arm vaccination is no longer practiced, but fresh calf-lymph used for each child, these accidental inoculations are a thing of the past. The ignorance of cause and effect is responsible for a great deal of the most childish objections to vaccination as to much else. One woman lately told me that she could not have her child vaccinated because a child in the same street was made a cripple for life by being vaccinated. Could we have a better example of the "post hoc sed non propter hoc."[7]
[7] Now and again, however, we have the sad spectacle of some one really well educated but apparently either ignorant of logic or desirous of wilfully misrepresenting facts. The Hon. Stephen Coleridge has an article in the June (1914) number of the Contemporary Review which is, to say the least of it, highly immoral in ethics and statistics.
I shall examine only that part of it bearing on vaccination. The statements are that in the last five recorded years, 58 persons died from smallpox vaccination (he means vaccination against smallpox), whereas in the same five years, 85 persons died from smallpox itself. The inference we are intended to draw from these figures is that to be vaccinated is nearly as fatal as to have smallpox itself.