microscopic picture at the costochondral junction differing widely from that seen in the acute stage. Not only are the columns of cartilage cells represented merely by misshapen vestiges, but an ossified band (Fig. 9) is seen at the junction. It is probable that this is frequently the cause of the marked cessation of growth which has been described in connection with this type of scurvy in infants. Delf and Tozer interpret this ossified band at the junction as "an attempt to strengthen the junction in an abnormal manner, the normal process having broken down." If the animal is again deprived of antiscorbutic food the ossified band breaks down, the junction becomes deformed and disorganized, and a condition of "chronic scurvy (acute)" is stated to have developed. [37] These changes are not found in every specimen, so that in order to be able to exclude scurvy definitely, it is necessary to examine a considerable number of ribs; several may be normal, only one or two showing the characteristic microscopic changes. [Illustration: FIG. 9.--Diagrammatic representation of guinea-pig scurvy (copied from Delf and Tozer by the courtesy of the Cambridge Press). 1. Diagram of normal rib-junction. 2. Diagram of rib-junction to illustrate "Incipient Scurvy." This rib-junction is very nearly normal, but shows what may be regarded as the first recognizable signs of the onset of the disease; these are: (_a_) An appearance of general abnormality (when compared with the normal). (_b_) Unevenness of the junction and slight disorganization of the rows of cartilage cells. (_c_) Shortening of the length of the rows of cartilage cells. (_d_) Shortening, and decrease in number of the trabeculæ. (_e_) Increased amount of blood in the marrow cavity. 3. Diagram of rib-junction to illustrate "Definite Scurvy." Histological signs vary considerably in these cases (according to the severity of the disease), and may approach in appearance those characteristic of the "Acute" condition. The rows of cartilage cells may be almost normal, but are more often noticeably shortened and usually somewhat disorganized or arranged in circular groups. The trabeculæ are usually about half the normal length and have a truncated appearance. The junction as a whole may present an uneven, slightly disorganized appearance and there is sometimes a certain amount of macroscopic deformity.