On Sunday the 5th of March I was sent for to a gentleman, of about 30 years of age, who had been for some days ill of a fever. I found him with a degree of heat considerably above what was natural, and with a pulse rather low, but quick, and beating, as measured by a stop-watch, about a hundred strokes in a minute. In this situation he continued, without any remarkable alteration, for the two following days; and, from the appearance of this disease, I imagined, that it would not be speedily terminated. On Wednesday, the third day of my seeing him, I found him however much better; his heat being considerably abated, and his pulse being more than twenty strokes in a minute slower than it had been the day before. On this alteration, so much in his favour, it might have been thought he was growing well, had it not been, that there was no appearance either by sweat or urine, or on the skin, by which it could be imagined the disease was perfectly judged. On this account no alteration was made in his treatment that day: but finding, the next morning, that he had slept well the preceding night, and that his pulse continued quiet, being no more than 74 strokes in a minute, he was allowed to get up in the evening, to have his bed made; and I should have thought him well, had not every appearance of a critical separation been still wanting. On this account, I thought him to be very liable to a return of his fever; and therefore, when early the next morning I was informed, that he had been without any sleep, and quite delirious, the whole night, I was not greatly alarmed, as thinking he had a feverish paroxysm, to which the bark would probably put an end. When I saw him that morning, I found him very delirious; but, to my great surprise, quite free from all kind of fever whatever; his pulse being then as calm as it had been the preceding day. In this condition he remained all that day, and the following night; nothing, that was attempted to relieve him, having done him the least service: on the contrary, his delirium increased so much, as to make it very difficult for the attendants to keep him in bed. The next morning he was much as he had been the day before; his imagination continuing greatly disturbed, and he at times laughing, and playing antic tricks, and using gestures the most opposite to his common demeanour when well; and which, tho’ the pulse had not been so perfectly quiet, had more the appearance of a _mania_, than of the delirium of a fever. In this unhappy situation, there was but one thing, which seemed likely to bring the affair to a speedy determination: this it was proper to attempt, tho’ the indications for it were very obscure, and the event perfectly uncertain. On recollecting the time of this delirium’s coming on, which was about 36 hours after the pulse had grown quiet; and perceiving, that one glass of the water, which had been made in the night, was thick, and seemed disposed to drop a sediment; there