There are probably few conditions which are more difficult to define than hysteria. It is unsatisfactory to make any attempt at generalisation with regard to hysteria, as so many exceptions can be found. It is my opinion that a great many distinct conditions are included under the name hysteria. These conditions are probably as different as epilepsy and migraine. All the various so-called hysterical conditions are closely related to insanity. In many families, whilst one or two of the members are insane, several others are hysterical, and others, again, suffer from allied nervous disorders. I will discuss the varieties of hysteria under the following heads: