Speaking generally, acute febrile processes in the present state of our knowledge, may be divided into two classes, those in which the febrile reaction, with its accompanying nervous manifestations, particularly brain symptoms, is due to the presence in the body fluids of soluble poisons, intoxication; and, secondly, those cases in which the febrile reaction or nervous manifestations are due to, or at least are accompanied by, distinct structural changes. How far the second class of cases may be hereafter shown to belong to the first class it is not our present purpose to discuss. Perhaps it would be better to present the same classification in different terms, and say that there are acute cases in which the symptoms may be made to disappear, promptly and completely, by active eliminative measures, and, secondly, cases in which elimination fails to relieve.
In practice it is difficult and often impossible to differentiate the