VII. The blood was dissolved in a few cases. That appearance of the blood, which has been compared to the washings of flesh, was very common. It was more or less sizy towards the close of the disease in most cases. I have suspected, from this circumstance, that this mark of ordinary morbid action or inflammation was in part the effect of the mercury acting upon the blood-vessels. It is well known that sizy blood generally accompanies a salivation. If this conjecture be well founded, it will not militate against the use of mercury in malignant fevers, for it shows that this valuable medicine possesses a power of changing an extraordinary and dangerous degree of morbid action in the blood-vessels to that which is more common and safe. I have seldom seen a yellow fever terminate fatally after the appearance of sizy blood. Dr. Stewart informed me, that in those cases in which the serum of the blood had a yellow colour, it imparted a saline taste only to his tongue. He was the more struck with this fact, as he perceived a strong bitter state upon his skin, in a severe attack of the yellow fever in 1793. I proceed next to take notice of the type of the fever. In many cases, it appeared in the form of a remitting and intermitting fever. The quotidian and tertian forms were most common. In Mr. Robert Wharton, it appeared in the form of a quartan. But it frequently assumed the character which is given of the same fever in Charleston, by Dr. Lining. It came on without chills, and continued without any remission for three days, after which the patient believed himself to be well, and sometimes rose from his bed, and applied to business. On the fourth or fifth day, the fever returned, and unless copious evacuations had been used in the early stage of the disease, it generally proved fatal. Sometimes the powers of the system were depressed below the return of active fever, and the patient sunk away by an easy death, without pain, heat, or a quick pulse. I have been much puzzled to distinguish a crisis of the fever on the third or fourth day, from the insidious appearance which has been described. It deceived me in 1793. It may be known by a preternatural coolness in the skin, and languor in the pulse, by an inability to sit up long without fatigue or faintness, by a dull eye, and by great depression of mind, or such a flow of spirits as sometimes to produce a declaration from the patient that "he feels too well." Where these symptoms appear, the patient should be informed of his danger, and urged to the continuance of such remedies as are proper for him. The following states or forms were observable in the fever: 1. In a few cases, the miasmata produced death in four and twenty hours, with convulsions, coma, or apoplexy. 2. There were _open_ cases, in which the pulse was full and tense as in a pleurisy or rheumatism, from the beginning to the end of the fever. They were generally attended with a good deal of pain.