The War Against Disease. Vaccination

In considering the great debates over evolution and vitalism, it is important to keep from forgetting that man's interest in biology as a science grew out of a preoccupation with medicine; with the disorders of the body. However far the science may fly off into the realm of theory and however serenely it may seem to hover beyond the concern of ordinary affairs of men, to that preoccupation it will return.

Nor is a concern with theory distracting or wasteful, for when, armed with an advance in theory, men turn to application of a science, how rapidly matters march. And although applied science may advance in a purely empirical fashion without theory, how slow and fumbling that is in comparison.

As an example, consider the history of infectious disease. Until nearly the dawn of the nineteenth century, doctors had been, by and large, helpless in the face of the vast plagues and epidemics that periodically swept across the land. And of the diseases that plagued mankind, one of the worst was smallpox. Not only did it spread like wildfire; not only did it kill one in three; but even those who survived were unfortunate, for their faces might easily be left so pitted and scarred that one could scarcely endure the sight of them.

One attack of smallpox, however, insured immunity to future attacks. For that reason, a very mild case of smallpox, leaving one virtually unscarred, was far, far better than none at all. In the former case, one was forever safe; in the latter, forever under the threat. In such places as Turkey and China, there were attempts, consequently, to catch the disease from those with mild cases. There was even deliberate inoculation with matter from the blisters produced by mild smallpox. The risk was terrible, for sometimes the disease, when caught, proved not mild at all in the new host.

In the early eighteenth century, such inoculation was introduced into England but did not really prove popular. However, the subject was in the air and under discussion and an English physician, Edward Jenner (1749-1823), began to consider the matter. There was an old-wives' tale in his native county of Gloucestershire to the effect that anyone who caught cowpox (a mild disease common to cattle that resembled smallpox in some ways) was thereafter immune not only to cowpox but to smallpox as well.

Jenner, after long and careful observation, decided to test this. On May 14, 1796, he found a milkmaid who had cowpox. He took the fluid from a blister on her hand and injected it into a boy who, of course, got cowpox in his turn. Two months later, he inoculated the boy again, not with cowpox, but with smallpox. It did not touch the youngster. In 1798, after repetition of the experiment, he published his findings. He coined the word "vaccination" to describe the technique. This is from the Latin word, “vaccinia” for cowpox, which, in turn, comes from the Latin word, “vacca”, for cow.

Such was the dread of smallpox that for once an advance was greeted and accepted with almost no suspicion. Vaccination spread like wildfire over Europe and the disease was vanquished. Smallpox has never since been a major problem in any of the medically advanced nations. It was the first serious disease in the history of mankind to be so rapidly and completely brought under control.

But the advance could not be followed up in the absence of appropriate theory. No one as yet knew the cause of infectious disease (smallpox or any other), and the accident of the existence of a mild cousin of a major disease which could be used for inoculative purposes was not to happen again. Biologists simply had to learn to manufacture their own mild versions of a disease, and that required more knowledge than they possessed in Jenner's time.