The arteries often suffer from _arteriosclerosis_, which is either diffuse or nodular. Endarteritis is a common manifestation of syphilis and leads frequently to the formation of aneurysm. Sometimes this appears as a single and large lesion; at other times hundreds of small aneurysms will form in the arterial system of the brain, so that the arteries are studded with them. The explanation of aneurysm under these circumstances is that the arterial walls, being weakened, dilate under the influence of blood pressure. Thus the arteries, from the largest to the smallest, also may suffer. The veins likewise are subject to syphilitic phlebitis, which is frequent in the superficial veins of the extremities. =Bones and Joints.=--Syphilitic manifestations in bones are frequent, but are not so common in the joints. While early syphilitic periostitis is not infrequent the actual lesions of the bone are mostly expressions of late syphilis. Nearly all of them are painful. The pain is worse at night, and is called the osteocopic pain of syphilis. At first these bone lesions are hyperplastic, because of the connective tissue in the bone. Periostitis is a common manifestation, and here, again, the neoplastic tendency of the disease is manifested, in that the periosteum is thickened as well as the bone beneath, and swellings called _nodes_ are thus formed. Nodes are met with more often on the tibia and the sternum than elsewhere, but are frequent upon the skull and clavicles. No bone is exempt from these lesions. They often form at points where there has been previous injury. These swellings are ill-defined, and usually quite tender, while the skin over them is easily movable unless secondary infection has occurred and suppuration is present. The nocturnal pains in these lesions, of which patients often complain, are sometimes excruciating. Should suppuration occur, with subsequent formation of ulcer, there may be necrosis of the exposed bone. Another bone lesion of syphilis assumes the type of _ostitis_. Physiologically this consists essentially of gummatous involvement of the connective tissue, which may be either localized or diffuse. When this undergoes retrocession there occurs a rarefaction of the bone, by which it is weakened and easily broken, so easily in fact that we have to deal sometimes with what is referred to as _spontaneous fracture_. There is frequently a thickening and condensation of the entire bone, with some distortion, so that the actual weight of the bone may be nearly doubled. _Dactylitis_ is the name given to syphilitic ostitis of the phalanges, which increase in size and become tender and useless, while the skin becomes glazed. Occasionally the disturbance appears to involve the extra-osseous tissues rather than the bones themselves. Bones which are spongy are liable to this disease. Some of the bones in the face are peculiarly susceptible; hence the loss of the bridge of the nose, or of a portion of the hard