In the respiratory tract we find, in the first place, the affections of the nose. The septum of the nose is often destroyed, and the nose sinks in, in the form of a triangle. The palate is sometimes destroyed already in the secondary stage, and the patient’s speech is greatly impaired. The syphilitic affections of the larynx cause extensive destructions of the organ and a permanent impairment of the phonation. Deformities of the trachea are not seldom the consequences of syphilis. Pneumonia may also be caused by syphilis. Infiltrations of the lungs are not such a rare occurrence. Gummata of the lungs may undergo the destructive process, and cavities are formed which are not infrequently diagnosed as tuberculosis. The circulatory system is very often affected by syphilis, in the form of arteriosclerosis. Gummata are sometimes found in all the muscular parts of the heart. Syphilitic myocarditis and sclerotic endocarditis are not rare. The syphilitic affection of the ganglia and the nerves of the heart are the cause of different forms of angina pectoris. The spleen and the other blood-producing organs, the bone-marrow, are frequently the seat of syphilitic manifestations. Pseudoleukaemia is often caused by syphilis. The different aneurisms are often caused by syphilis of the arteries. The genito-urinary system is especially affected by syphilis. Apart from the initial affection, which is usually found at the genitals, tertiary syphilis of the genital organs is not rare. Syphilitic orchitis and gummata of the penis and testicles are often observed. Gummata are also found on the external genitals of women. The ovaries are often affected in form of diffuse or gummatous oöphoritis. Syphilis is not seldom the etiological factor of Bright’s disease. The skeleton is also often affectedly syphilis. Besides the bone-marrow, the bones themselves are especially subject to syphilitic lesions. No joint escapes the attack of syphilis. The most frequently affected joints are the knees and the elbows. The muscles are affected by syphilis in form of an irritative myositis and of chronic interstitial inflammations. Gummatous infiltrations of the muscles are no rarity. The tendons are affected in form of an acute irritative tendo-synovitis. Swelling of the bursae is quite frequently met with in syphilitic patients.