In 1792 Jenner applied to the University of St. Andrews for the degree of Doctor of Physic. It cost £15, and nothing more.
Hunter used to say to speculative pupils, “Don’t think, but try; be patient, be accurate;” and Jenner, in relation to cowpox, required the advice; for, by his own account, he was content to think of cowpox for at least a quarter of a century, whilst he knew by intuition its true origin, its magical efficacy, and future triumph without any trial. His first experiment was made in November, 1789, upon his son Edward, his first-born, an infant of eighteen months.
“He was inoculated with cowpox?”
O, no!
“Then with grease from a horse’s heel?”
Not at all!
“With what then?”
Why, with swinepox; and it answered!
The child sickened on the eighth day; a few pustules appeared; they were late and slow in their progress, and small, but they proved sufficient. The poor child was then put through what was styled the Variolous Test: not once or twice, but five or six times at various intervals, he was inoculated with smallpox without other obvious effect than local inflammation and erysipelas. Nothing ever claimed for cowpox turned out more satisfactorily than this experiment with swinepox—supposing we trust Jenner.
Arguing from the records (and we have nothing else to argue from) it was not until about 1795 that Jenner turned his attention with serious purpose to cowpox. This Baron allows, saying—