When skin lesions are clustered, as in the macular and papular forms, they usually group themselves symmetrically and in more or less circular outline. When, however, they are too regularly arranged, it may be taken as evidence of their older and more relapsing character. The later skin lesions of syphilis differ in several respects from the earlier. They are less regularly grouped; they involve a greater depth of tissue; they tend to ulcerate and to leave permanent scars; and they have around them a more infiltrated area, probably because they are deeper. They are, however, not so infectious as the earlier lesions, and it is rare that they are of serious menace to others. (See Plates VIII, IX, X.) Fordyce and others have pointed out that the prompt and specific influence of mercury and even of iodine upon these eruptions is an instance of the selective action of certain drugs, and nothing could be more conspicuous in demonstrating it. Certain types of syphilide are common in the earlier stages and others in the later; there may be a well-defined limit between the two, since in not a few instances all types seem to be combined. The first eruption of so-called secondary syphilis assumes the erythematous or macular type, and has been referred to as _roseola syphilitica_. It appears as a generalized eruption, in spots varying from 0.5 to 1 Cm. in size, which are of a vivid color and scarcely elevated above the surface. It commences usually upon the abdomen, proceeds to the chest, and then to the extremities. It does not often appear upon the face. Two or three weeks may be consumed in its generalization over the entire body. If let alone it has a duration of a few days to several weeks, and may then fade away, leaving nothing to indicate its presence save a slight pigmentation. Of more pronounced character is the _papular_ eruption, which commences as a small papule, and is described as _lenticulopapular_ and _miliary papular_. At first these are generalized, then become circumscribed, and exhibit transition forms from the early to the later type of lesions. The papules vary in size from that of a millet-seed to that of a split pea; even this type may disappear without ulceration or suppuration. Lichen planus may be mistaken for papular syphilide, but may be distinguished from it by intense itching and by lack of the pigment changes which characterize the syphilide.