“M. Strack, professor of medicine at Mayence, in a letter upon inoculation, addressed to M. Roux in 1765, (Journ. de Med. tom. xxii.) maintains that natural Small Pox do not, any more than the artificial, protect against a second attack. In proof of his opinion, he mentions six cases of secondary Small Pox which he himself had attended. The argument which he uses in support of inoculation, in opposition to those who were hostile to that practice, and who asserted that it does not protect against a subsequent attack, though novel at the time it was employed, has since been sufficiently confirmed by repeated observation. He says, that those who have passed through the Small Pox twice, whether naturally or artificially, have, in general, escaped without danger; those patients, he adds, who have had the Small Pox at two different periods, are fortunate, because if the variolous miasma had operated with its full force during the first attack, they probably would have fallen victims to the disease” (p. 77). Mr. Moore remarks (Hist. of Small Pox, p. 278) that, “besides the foreign authorities, the English Medical Journals contain several authentic examples of persons whose faces were strongly pitted with Small Pox, and who were afterwards destroyed by a second attack of that disease,”—he goes on (p. 279) to relate “an incident frequently repeated by the late Dr. Reynolds, Physician to his Majesty, who was sent for by a lady unknown to him, and conducted by her maid, rather mysteriously, into a handsome bed-chamber; where he saw, lying in a splendid bed, a lady masked. Being a good deal surprised, the maid stifled a laugh, while her mistress, in a soft toned voice, apologised for concealing herself even from a professional gentleman. This (she said) had become proper, from the peculiarity of her situation. At present she stood greatly in need of his superior medical talents, and was extremely anxious for his opinion on her case, which she understood from others, was a very rare one. The doctor being thus put upon his guard, enquired minutely into all the symptoms, and examined critically a pustular eruption which was spread over the lady’s person: he then pronounced the disease to be, without all doubt, the Small Pox. On which the patient unmasked, and displayed features seamed with the disorder.” Dr. Thomson (in his Historical Sketch, p. 279) informs us, that out of _eight hundred and thirteen_ cases of Small Pox, which had come under his notice since June, 1818, “_seventy-one_ had previously passed through Small Pox.” And in the sequel many other instances will be referred to.