There always must be some awkwardness about the classification of insanity. It is regarded as aberration of function of the nervous centres, the result of a number of nervous diseases. The physician who wishes to have a proper know ledge of insanity from a medical point of view must study the pathological conditions of which it is the symptom or the result, and when he has done so it is impossible for him to disconnect one series of observations from the other-the mental aberration from the accompanying disaese of tissue or pathological symptoms.

Euripides introduces the story of Orestes into three of his tragedies, which were written at different times, and on no common plan; but they, nevertheless, follow the same general manner of treating the subject. Sophocles had apparently felt that he coxild best introduce novelty into the treatment of a subject already dramatized by the master hand of Æschylus, by bringing into prominence the sufferings of Electra, and her delivery by her brother Orestes. Euripides followed the same idea, and went farther.

The terse, but comprehensive expression of John Hunter contains in a nutshell the principle which underlies the greater part of the phenomena referred to in this section: “I am confident,” he says, “that I can fix my attention to any part until I have a sensation in that part.” Müller expresses the fact of the operation of the ideational upon the sensational centres in equally clear terms.