This mode of treatment may be repeated in two or three weeks and has the tendency of breaking up the shiny line of light that makes the scar stand out prominently from the skin. Such scars, where nonadherent, or flat with the plane of the skin, may also be tattooed to reduce their white color. For this purpose, the red or carmine pigment used for tattooing is diluted and pricked into the scar tissue with a fine cambric needle by hand or electric process. When the scar is small the line is punctured here and there and the aqueous solution of the pigment is painted over the area, which is again worked over to make it take. For larger scar surfaces multiple needles are used. These are composed of from four to ten needles soldered together at their eye ends, leaving the points at an even level. The electric method is the most serviceable for tattooing large scars. These instruments are electro-magnetic devices made to accommodate single or multiple needle points and can be obtained from instrument makers. The author has had a special electric synchronous reciprocal apparatus made, as here shown in Fig. 520, which is much more compact than the ordinary electric apparatus found on the market. It works on the principle of the sewing machine needle. [Illustration: FIG. 520.—AUTHOR’S ELECTRIC APPARATUS FOR TATTOOING SCARS.] In using the electric apparatus the needle ends are dipped into the pigment paste, to which a little glycerin is added to bind it, and this is tattooed or pricked into the scar. If, after the parts are healed, the color is too light, the scar may again be gone over until the tint matches somewhat the tint of the skin. Other pigments may be used, according to the complexion of the patient. Some scars, the resultant of negligent coaptation, are to be excised according to the Celsus method and are brought together with a number of fine silk sutures. If the skin is found to be attached too closely to the subcutaneous structure, it must be dissected up to render it mobile. When the scar cannot be removed by excision the hypodermic use of thiosinamin may be tried. Thiosinamin or rhodallin is only slightly soluble in water, but the addition of antipyrin according to _Michel_ renders it useful for hypodermic use. The formula preferred by the author is made as follows: ℞ Thiosinamin grs. ij Antipyrin grs. j Aqua dest. gtts. xx. The above solution makes up a single injection, which is to be made directly under the scar or into the muscular tissue below it. Two injections are given each week. The treatment is to be continued until the texture of the cicatrix is equal to that of the skin. These injections are more or less painful and may be supplanted to advantage with the hypodermic use of fibrolysin (_Mendel_), in which each 2.3 c.c. correspond to three grains of thiosinamin.