Something of Jenner's enthusiasm for experiment may be gathered from the fact that he did not hesitate even to inject various materials related to cowpox into the arm of his own children. We know Mrs. Jenner to have been a very wonderful woman, quite as deeply interested as the doctor himself in securing the great benefit to humanity that would result from the demonstration that cowpox protected against smallpox, but it is a little bit difficult for us in these days to understand how her mother-heart could have permitted some of the experiments which Dr. Jenner's biographer, Dr. Baron, describes. [Footnote 1] [Footnote 1: The life of Edward Jenner, M.D., F.R.S., Physician Extraordinary to His Majesty Geo. IV, Foreign Associate of the National Institute of France, &c. &c. &c. With illustrations of his doctrines, and selections from his Correspondence by John Baron, M.D., F.R.S., Late Senior Physician to the General Infirmary, Consulting Physician to the Lunatic Asylum at Gloucester, and Fellow of the Royal Medical and Chirurgical Society of London. In two Volumes. London: Henry Colburn, 1838.] The subject is indeed so surprising that I prefer to quote the passage with regard to these experiments directly from Dr. Baron: "In November, 1789, he inoculated his eldest son Edward, who was then about one year and a half old, with swine-pox matter. The progress of the disease seemed similar to that which arises from the insertion of true smallpox matter when {97} the disease is very slight. He sickened on the eighth day: a few pustules appeared; they were late and slow in their progress, and small. Variolous matter (this would mean material from a smallpox patient calculated to give that disease) was carefully inserted into his arms at five or six different periods, subsequently without the slightest inflammation being excited in the part. "On Thursday, April 7th, 1791, variolous matter was again inserted by two small incisions through the cutis, [beneath the skin]. Then the following notes of observed conditions day after day are made: 9th, Evidently inflamed. 10th, An efflorescence of the size of a shilling spread round the inferior wound. 11th, The incision assumed a kind of erysipelatous elevation: the efflorescence much increased. 12th, These appearances much advanced. 13th, A vesicle, containing a brownish fluid, and transparent, about the size of a large split-pea on the superior incision, the inferior about twice as big; the surrounding parts affected with erysipelas. The erysipelas extended to the shoulder, and then pretty quickly went off. The child showed no signs of indisposition the whole time."