DISEASE, according to its literal construction, a state of disease, or absence of the condition of health, in which all the faculties and organs of the body and mind work together harmoniously and without sensible disturbance. In a strictly scientific sense, there may be disease without pain or uneasiness in the ordinary meaning of these words, but hardly without functional disturbance or incapacity of some kind. It is, therefore, only necessary to include in the definition of disease the diminution of func tional power, whether attended or not by suffering, and the scientific and practical ideas of the word will closely correspond. It must be. admitted that slight structural and functional deviations from the state of health are sometimes unnoticed; but only because they are slight, and because the functions to which they extend are not habitu ally in use to the full extent. A great deal of unnecessary obscurity is found, especially in continental writers, in discussing the abstract idea of disease, which has been con nected with all the most intangible subtleties of the most abstruse and metaphysical philo sophy, by regarding it as dependent upon the idea of life and of the vital force. Many authorities have thus generalized disease into a separate active, principle, opposed to, and everywhere seeking to destroy, the principle of health; and Paracelsus was hardly more open to objection on the ground of absurdity than many others of his countrymen, when, in his picturesque and at the same time mystical manner, be endowed the vital principle with a kind of personality, and spoke of disease as due to the whims and cap rices of a displeased and resentful Archmus, an idea which was still further developed by Van Helmont. It is common to treat of disease as being functional or manic; i.e.,
evidenced by changes of function or of structure; but function and structure are so closely allied in fact and in nature, that the more this distinction is examined the more vague and impalpable it becomes; and it can therefore only be kept up as a provisional and conventional arrangement. The classification and arrangement of diseases accord ing to their external characters has been termed nosology (q.v.); while the observation of their more intimate and less superficial relations in connection with their causes and results, is called pathology (q.v ); both of these sciences, of course, being kept in view in the healing art of medicine (q.v.), of the more practical portion of which they form the pillars.