steep, sometimes slightly thickened, and the scalp separated from the brain only by a thin, transparent membrane, the remnant of the periosteum. These holes can be easily found through the integument. The finger, though ever so gently pressing down upon it, moves the cranium, if any be left, before it; the bone feels like paper, and the sensation as if it could be easily broken through is quite distinct and embarrassing. Such perforations are usually quite numerous; from five to twenty or more can often be counted. They are surrounded by normally hard bone, and thereby can be recognized from the flexible part of the cranium extending along the sagittal and lambdoid sutures. Where these results of rachitical softening, craniotabes, are most prominent--that is, on the part on which the infant is mostly reclining--the bone is flattened, and may remain so for life, though in the majority of cases the asymmetry will disappear. The flattening and perforations result from the same causes--viz. softening of the bones and pressure upon the bone between the pillow outside and the brain inside. With it go, hand in hand, thick rachitical deposits under the hyperæmic periosteum of other portions of the skull. Where craniotabes is largely developed on the occipital portion, the frontal and the parietal bones (in their anterior halves) are usually thus thickened. A cross-section with a knife will reveal a diameter of the new osteoid material between the periosteum and bone of one-half to one centimeter in thickness. It is very hyperæmic--even more so than the bone itself, {148} which, when cut into, exhibits an unusual amount of blood. Sometimes the deposits are still larger, and are apt to change the appearance and weight of the skull considerably after recovery has taken place and eburnation and sclerosis have taken the place of the normal osseous tissue. [Footnote 13: Boötius (1649), quoted by Haller (_Bibl. Med. pract._, 1779): "Infantibus caput grandescit, reliquum corpus contabescit, ossa in articulis tument, dextrum hypochondrium tumore æquali prominet; hoc malum multis millibus infantum molestum est" ("The infant head grows large, the rest of the body emaciates, the articular bones swell, the right hypochondrium is raised by a uniform tumor; this malady is a sore affection in many thousands of infants").]