(_a_) Whenever in apparently favorable cases there are signs of injury to the base of the brain, such as paralysis of cranial nerves, {98} neuro-retinitis, and Cheyne-Stokes respiration (although the last symptom may occur from simple compression). (_b_) When hemispasm or hemiplegia is accompanied by hemianæsthesia, thus making it probable that the lesion is deeper and farther back. It should be added, in conclusion, that these indications and contraindications are formulated from the standpoint of the neurologist. {99} MENTAL DISEASES. BY CHARLES F. FOLSOM, M.D. DEFINITIONS OF INSANITY.—The term insanity conveys quite different meanings to the community, to lawyers, and to physicians. From the three points of view its definition has been constantly widening for the past century. A great part of the alleged recent increase in insanity is due to the fact that its definition is applied to more people. Our insane asylums are more quiet and orderly, not only because of the more humane treatment of the inmates, but largely also because quieter and less insane people are now sent there than formerly. Doubtless the mistake is sometimes made of going so far, in zeal for science and philanthropy, as to make the definition of insanity too broad; and in a refined civilization the nice adjustment of complicated social relations, or even a fastidious taste, requires people to be sent to insane asylums who in simpler states of society would be cared for at home.[1] [Footnote 1: The physician in general practice is referred to Clouston's _Clinical Lectures on Mental Diseases_, and to Part 1 of Spitzka's _Manual of Insanity_. For those who wish to study insanity thoroughly the literature is rich and its bibliography is readily available. Of many parts of the subject only an outline, of course, can be given within the limits of the present paper.]