=Symptoms.=--Let us consider the symptomatology of guinea-pig scurvy. In the course of an observation of many hundreds of animals we have been struck by the striking uniformity of the signs and symptoms. The animals made use of were almost invariably of moderate size, weighing from 200 to 300 grams. Where heavier pigs were employed the disease progressed less rapidly, but the signs were the same; they were, however, more difficult to elicit, owing to the subcutaneous fat. Most of the animals were on a diet of hay, oats and water _ad libitum_, but there was no variation in symptoms where fat and fat-soluble vitamine were supplied by an addition of egg yolk or of cod liver oil, or where egg albumen was fed to render the protein adequate, or where the inorganic salts were supplemented by additions of sodium or calcium chloride. There is a variability in the sign which signalizes the onset of the disorder--sometimes it consists of a flattening of the weight curve, at others of an inordinate excitability of the animal, or frequently of a tender joint, generally a wrist. The joints almost invariably become tender early in the disease, causing the animal to wince and cry when it is examined. Accompanying this tenderness there is often slight swelling due to edema, or perhaps some hemorrhage, which alters the sharp, clean-cut contour of the joint. This edema may extend upward along the tendon sheaths. Soon the animal becomes lethargic rather than nervously active, and may look ill, as manifested by a roughness of its coat and its unnatural posture. Frequently it sits on three legs with the tender hind leg drawn upward and outward so as to escape pressure--a posture termed by Chick, Hume and Skelton (1918, 2) "_the scurvy position_," and indicative of hemorrhage into the joints or muscles. At times it lies curled up, with the side of its face resting on the floor, as if to support its painful or sensitive jaw; this they have termed the "_face-ache position_." The two diagnostic signs, however, are the hemorrhages about the joints and the loosening of the teeth. The diagnosis frequently can be established by the twelfth to the fourteenth day; the earliest diagnosis was made on the eighth day. Hemorrhages appear somewhat later than tenderness, and are situated at the joints, most frequently at the knee, which may be markedly swollen and show a bluish or reddish discoloration, extending upward or downward for some distance. Other joints are often involved, frequently the wrist, the ankle or the shoulder. In other cases hemorrhages into the muscles are noted, especially of the leg or of the thigh, and later, especially toward the end, hemorrhages from the bowel. Fractures or separations of the epiphyses may be found on examination or may be occasioned by the physical examination. A frequent site of this lesion is at the wrist or at the knee, involving the head of the tibia or the lower end of the femur.