I received several accounts of the good effects of mercury from the gentlemen in the pest-houses, but none so remarkable as the following:—In the beginning of the season, on the breaking out of the disease in the crowded hospital of the 88th regiment; every man in the hospital was examined at different periods of the day, and thus the disease was detected on its very first appearance. At this time, I gave to each of three of the men, placed in the observation-ward of the hospital, (of whom Littlejohn and Egan have already been mentioned,) two grains of calomel, and the sixth of a grain of opium every hour, and made them rub into the inside of the legs, thighs, arms, and neck, half an ounce of the strong mercurial ointment three times a day. I, at the same time, made them take each half an ounce of nitric acid diluted in their drink during the day, and put their feet and hands, three times during the day, into a strong nitric bath. In about twenty-four hours, their mouths became severely affected, a tenderness in their arm-pits and groins went off, and the severest febrile symptoms yielded. The men were, however, extremely debilitated, and remained a very long time convalescent. During their convalescence, I thought it prudent to keep them in quarantine, being fully convinced, that they had had an attack of the plague, the progress of which had been arrested, and the disease cut short by the above treatment. Corporal Francis, as already mentioned, was suddenly attacked with giddiness after coming off from duty as corporal of the guard in the pest-house. In the very commencement of the disease, on the first feeling of illness, he was brought to Mr Price, who instantly admitted him and immediately exhibited mercury, and as soon as the gums became affected, the febrile symptoms vanished. He remained some time in the hospital, on account of a bubo, which came to suppuration; but Francis suffered very little. He was never more than two days confined to bed, though the case occurred at a time when the disease was very violent. The case of Peter the interpreter strongly evinces the success of the mercurial treatment. To this case, the mercurial pills and ointment were given; and he was, in every respect, treated as a case of syphilis and was speedily cured. In the cases related, there appeared some facts as to the time the matter of the pestilential contagion takes before it comes into action. Other facts shew, that, in different people, and under different circumstances, there is the greatest variety in this. The lazaretto at Alexandria was infected by the admission of an Italian merchant, and the guard there, consisting of 14 men, caught the disease, but were attacked on different days. The provost’s guard and his prisoners at Alexandria caught the infection from a deserter confined among them, and the disease among these people appeared at very different periods.