In everyday Euro-American understandings, blood is both vital and dangerous to the brain. Why, then, are there virtually no illustrations of the brain in contemporary neuroscience that include the blood vessels needed to supply the brain with its vital energy? Photographs, drawings, scans, images, and other kinds of visual material illustrate the location, function, and shape of nervous tissue in the brain in endless variety and detail. But to see where the blood vessels that supply the brain lie, one has to turn to texts on the anatomy of cerebral vasculature or medical literature specifically devoted to the diagnosis and treatment of brain injury. Blood is simultaneously essential to contemporary understandings of brain physiology and segregated into distinct domains. Using visual depictions in medical illustrations and web-based discussions among patients with brain injury, this paper explores what kind of special object blood is in contemporary neuroscience.