Pain in the head, or giddiness, or some other uneasy sensation in this organ, attended with a loss of sleep and with a derangement in all the sensorial faculties,—these are the signs of the presence of the disease in the brain or its membranes. Pain in the back, loins, or limbs, or diminution of the power of voluntary motion—these are the signs which mark the existence of the disease in the spinal cord or its membranes. These symptoms having been present a certain time, and at length succeeded by—diminution of the pain or uneasiness _without a corresponding diminution in the other febrile symptoms_, but with an _increase_ in _some_ of them; for instance, with an increase of the sleeplessness and restlessness: at last, total cessation of all pain or uneasiness, together with a diminution of the sensibility—these are the signs which mark the progress of the disease, and which, in general, denote a transition from the state of mere inflammation to the formation of some inflammatory product. Thus far the change of state is certain and the signs which denote it invariable; to the latter other symptoms are added which occur in the great majority of cases, but not in all; namely, delirium, muscular tremor, involuntary and unconscious stools, acceleration, and in general, increased and increasing weakness of the pulse. Other accessory symptoms still frequently occur and with considerable regularity, but as these are more variable the student is referred to the cases themselves, the study of which can alone teach when they may be expected.