The mind suffered with the morbid states of the brain and nerves. A delirium was a common symptom. It alternated in some cases with the exacerbations and remissions of the fever. In some, it continued without a remission, until a few hours before death. Many, however, passed through the whole course of the disease without the least derangement in their ideas, even where there were evident signs of a morbid congestion in the brain. Some were seized with maniacal symptoms. In these there was an _apparent_ absence of fever. Such was the degree of this mania in one man, that he stripped off his shirt, left his bed, and ran through the streets, with no other covering than a napkin on his head, at 8 o'clock at night, to the great terror of all who met him. The symptoms of mania occurred most frequently towards the close of the disease, and sometimes continued for many days and weeks, after all other febrile symptoms had disappeared. The temper was much affected in this fever. There were few in whom it did not produce great depression of spirits. This was the case in many, in whom pious habits had subdued the fear of death. In some the temper became very irritable. Two cases of this kind came under my notice, in persons who, in good health, were distinguished for uncommon sweetness of disposition and manners. I observed in several persons the operations of the understanding to be unimpaired, throughout the whole course of the fever, who retained no remembrance of any thing that passed in their sickness. My pupil, Mr. Fisher, furnished a remarkable example of this correctness of understanding, with a suspension of memory. He neither said nor did any thing, during his illness, that indicated the least derangement of mind, and yet he recollected nothing that passed in his room, except my visits to him. His memory awakened upon my taking him by the hand, on the morning of the 6th day of his disease, and congratulating him upon his escape from the grave. In some, there was a weakness, or total defect of memory, for several weeks after their recovery. Dr. Woodhouse informed me that he had met with a woman, who, after she had recovered, could not recollect her own name. Perhaps it would be proper to rank that self-deception with respect to the nature and danger of the disease, which was so universal, among the instances of derangement of mind.