The hypothesis of vagotonia and sympathicotonia, established by Eppinger and Hess,1 gave a clearer explanation of diseases whose pathology was heretofore not quite obvious, thereby opening a new way to diagnosis and treatment.
According to their orginal opinion, there exists an equilibrium between the sympathetic and autonomic (parasympathetic) nervous systems, through which the inner organs and the involuntary apparatus perform their functions smoothly. When this equilibrium is once disturbed, however, from any cause, the action of one becomes predominant, and various pathologic conditions arise. By means of drugs which act especially on the vegetative nervous system, this disturbance becomes so marked that it greatly facilitates the diagnosis.
This disturbance is due to the abnormal tonus of either the sympathetic or autonomic nervous system; in other words, everybody who is sensitive to atropin and pilocarpin is not sensitive to epinephrin, and vice versa. They named the former condition vagotonia, the