Besides the irregularity of the epiphyseal line, three other changes are seen in the bones of syphilitic infection. The most common lesion is one which affects the periosteum and leads to the formation of periosteal bone. This periosteal formation may occur either in congenital or in acquired syphilis, and it may affect one or many bones. In some cases there is an enormous thickening of the epiphysis of the bones, and as a result of the epiphyseal thickening, secondary changes in the joints occur, so that the thickening of bones and the changes in the facets of the joints, suggest fracture or dislocation. In other cases, the thickening affects only the shafts of the long bones, generally of the leg or arm, although no bones are exempt. In some cases, both in the congenital and acquired forms, there may be marked proliferation of the endosteum of the bone, with or without thickening of the periosteum, although thickening of the periosteum usually is present. This process, as a rule, affects one bone in its entirety, and most commonly affects the bones of the lower leg, notably the tibia. As a result of these changes the bones are enlarged and thickened, and in some cases, from endosteal thickening, the marrow canal is very largely or entirely obliterated. In some cases true gummata of the bone are formed. These gummata may appear in the spongy portion of the bone, sometimes in the shaft, or in the epiphysis. They also appear to be formed in the lower layers of the periosteum and lead to circumscribed nodular thickenings on the surface of the bone. +Symptoms.+ These vary with the different pathologic conditions present. The periosteal thickening may occur at any time of life over any bone of the body. The presence of circumscribed periosteal thickening of bone in itself should always lead to the suspicion of the presence of syphilis. Pain, as a rule, is only very slight, and the diagnosis depends upon the history and the detection of other syphilitic lesions. The cases in which there is both endosteal and periosteal thickening, occur chiefly in children and are of a congenital nature. The physical symptoms are very characteristic. The bone usually affected is the tibia, which is enlarged to a most marked degree, and often shows a pronounced bowing forward, similar to the bowing and thickening of the tibia seen in osteitis deformans. The bone is extremely dense and obviously heavier than normal. The bones are moderately tender to pressure, but have nothing like the extreme tenderness noted on pressure in osteomyelitic bones. In cases of gummata of bones the symptoms vary. In some cases the gummata are on the surface of the bone, especially the sternum, and at times on the long bones. In such cases there appear a softening and reddening of the skin about the affected area, which remains indolent for a long time.