4. Diagram of rib-junction to illustrate "Acute Scurvy." In these cases the junction and rows of cartilage cells are often completely disorganized, causing a marked macroscopic deformity of the bone. The bone of the shaft is frequently fractured. The marrow is no longer in contact with the edge of the junction and the space is filled with a mass of connective tissue; this is very characteristic in cases of fracture. A condition in which the trabeculæ have almost disappeared and the rows are much shortened is also found in "Acute Scurvy," in those ribs in which no fracture of the shaft has occurred; usually, however, there is little or no ossification across the junction. There is frequently hemorrhage into the marrow cavity. Diagrams 5 and 6 illustrate types of "Chronic Scurvy." 5. May be described as "Chronic Definite Scurvy." The rows are much shortened but not disorganized and an ossified band extends across the junction. 6. May be described as "Acute Chronic Scurvy." The junction is deformed, and the rows are very disorganized; the trabeculæ have disappeared and an ossified band extends across the junction. There is no connective tissue to be seen and no existing, or recent, fracture.] It has been noted by many investigators that _changes in the teeth_ take place in the course of scurvy. They become somewhat yellow and lose their glistening appearance, and occasionally break off. The molars commonly become loosened, so that they can readily be removed from their alveolar sockets; less frequently this is true of the incisors. Until recently, however, this subject has not been studied in detail, and no significant histologic changes in the teeth have been described. Jackson and Moore showed that with marked changes in the teeth there was often "great dilatation of the veins in the pulp attended by more or less hemorrhage into the pulp," and that "in guinea-pigs fed on oats and hay there was almost complete necrosis of the pulp of the incisor teeth, also more or less necrosis in the pulp of the molars."