The changes in the retinal vessels have been studied with peculiar attention since the beginning of clinical ophthalmology, as the background of the eye is the only place in the body where small arteries and veins, precapillaries and even capillaries can be observed covered only by a crystal clear tissue, in their natural position and color and magnified. Because of these favorable circumstances, important conclusions as to the pathology of the circulatory apparatus were naturally expected from such examinations. The importance of such conclusions, however, has increased considerably, owing to the knowledge that an almost complete parallelism exists between the retinal vessels and the cerebral vessels and that therefore one has an undisputed right to draw conclusions as to the condition of the cerebral vessels on the basis of changes in the vessels of the fundus.
I shall discuss briefly these changes.
The alterations of pure arteriosclerosis, not combined with