[18] Historia Anatomica Medica, vol ii. obs. 405, 418, 423, 510. [19] Medical Histories and Reflections, p. 150. I am the more inclined to believe the peculiarity in the pulse which has been mentioned in the yellow fever, arose in part from a spasmodic affection of the heart, from the frequency of an uncommon palpitation of this muscle, which I discovered in this disease, more especially in old people. The disposition, likewise, to syncope and sighing, which so often occurred, can be explained upon no other principle than inflammation, spasm, dilatation, or congestion in the heart. After the 10th of September this undescribable or _sulky_ pulse (for by the latter epithet I sometimes called it) became less observable, and, in proportion as the weather became cool, it totally disappeared. It was gradually succeeded by a pulse full, tense, quick, and as frequent as in pleurisy or rheumatism. It differed, however, from a pleuritic or rheumatic pulse, in imparting a very different sensation to the fingers. No two strokes seemed to be exactly alike. Its action was of a hobbling nature. It was at this time so familiar to me that I think I could have distinguished the disease by it without seeing the patient. It was remarkable that this pulse attended the yellow fever even when it appeared in the mild form of an intermittent, and in those cases where the patients were able to walk about or go abroad. It was nearly as _tense_ in the remissions and intermissions of the fever as it was in the exacerbations. It was an alarming symptom, and when the only remedy which was effectual to remove it was neglected, such a change in the system was induced as frequently brought on death in a few days. This change of the pulse, from extreme lowness to fulness and activity, appeared to be owing to the diminution of the heat of the weather, which, by its stimulus, added to that of the remote cause, had induced those symptoms of depression of the pulse which have been mentioned. The pulse most frequently lessened in its fulness, and became gradually weak, frequent, and imperceptible before death, but I met with several cases in which it was full, active, and even tense in the last hours of life.