Tumours of the brain have long been recognised as a cause of insanity, but different authors have regarded them in very different lights. Arnold quotes Morgagni and Bonetus, that tumours are one of 47 pathological changes found in the brains of the insane. Esquirol mentions them as among the morbid conditions found in the brains of the insane, but did not connect them with any particular symptoms. According to French statistics they occurred in the form of cancer in 22 out of 8,289 cases, that is, about 2·7 per 1,000. Dr. Sutherland mentions that he found 4 in 200 cases, or 20 per 1,000 cases. Tuke and Bucknill say that they only found 1 tumour in 400 autopsies, or 2·5 per 1,000. Leubuscher found tumours of the brain in four cases out of 358 autopsies, or at the rate of 11 5 per 1000. Fischer found not one case of tumour in 318 autopsies at the Prague Asylum. At the Carlisle Asylum we have performed 214 autopsies, and there have been 6 cases of tumours of the brain, which is at the rate of 28 per 1,000 cases.