Mania is the term applied to that large class of mental disorders in which the functions are in a state of excitement, and their mutual dependence and proportion disturbed. It embraces forms of disease so widely apart from each other, that in treating practically of its diagnosis it will be essential to make some classification. For practical purposes it will be sufficient to distinguish its forms into those of acute mania, comprising cases which present recent and active symptoms; chronic mania, in which acute symptoms have given way to others of a more tranquil and permanent kind; and incomplete mania, corresponding to the “mania raisonante” of the French, and embracing those anomalous and undeveloped forms of mental disorder in which defective power of volition and morbid propensities are prominent symptoms.