Several practical matters should be borne in mind in connection with this subject of the condition of the eye-ground. In the first place, sight is not always impaired in cases of even somewhat advanced choking of the disc, so that when other symptoms and indications lead to the suspicion of a brain tumor, unexpected confirmation may be obtained by ophthalmoscopic examination. Some remarkable cases of this kind have been reported, and doubtless have been observed by all ophthalmologists and neurologists of large practice. In some cases of growths of large dimensions also careful ophthalmoscopic examination has shown neither choked disc nor neuro-retinitis to be present. In two of Seguin's cases, for instance (Cases 28 and 29), these appearances were absent. In one he reports no neuro-retinitis, but only some fulness of the veins. In the other, a large sarcoma of the centrum ovale, ophthalmoscopic changes were absent. The absence of disturbance of vision, therefore, should not lead the physician to overlook making a thorough ophthalmoscopic examination; nor should the absence of ophthalmoscopic appearances lead him to make up his mind that serious intracranial disease was not present. The presence of double choked discs is in the highest degree significant of a brain tumor.
Observations on the temperature of the head have been made in a few cases of tumor of the brain. Full accounts of such observations in two cases (1 and 3 of Table) have been published by one of us.14 It is not within the scope of the present paper to review the general subject of cranial or cerebral thermometry. We will simply, in passing, recall the labors of E. Seguin,15 Broca,16 Gray,17 Lombard,18 Maragliano and Seppilli,19 and Amidon.20
14 Philadelphia Medical Times, Jan. 18, 1879, and New York Medical Record, Aug. 9, 1879.
15 Medical Thermometry and Human Temperature, by E. Seguin, M.D., New York, 1876.
16 Progrès médical, 1877.
17 New York Medical Journal, Aug., 1878.
18 Experimental Researches on the Temperature of the Head, London, 1881.
19 Quoted in Archives of Medicine, 1879.
20 Archives of Medicine, April, 1880.
L. C. Gray21 has recorded some observations in cerebral thermometry in one case of tumor of the brain. The tumor, a soft jelly-like mass the size of a hazelnut, was found between the horizontal branch of the Sylvian fissure and the first temporal fissure, while the whole of the right occipital lobe was converted into a colloid, extremely vascular mass, which gave way under examination, this degeneration also extending anteriorly to the tumor as far as the fissure of Sylvius. Microscopical examination showed it to be a typical glioma.