The literature of the last half of the nineteenth century contains many reports of syphilitic infection implanted during tattooing, sometimes in epidemic form, as brought out by Maury and Dulles.1 However, only after the beginning of the twentieth century does one find reports of an unusual distribution of the secondary syphilitic eruption in relation to tattooed figures in the skin.
In the earliest reports attention was called only to an accentuation of the secondary eruption in and near the tattoo; in the later reports, for the most part, an accentuation of secondary papules in the blue portion of tattoo was emphasized, while the bright red portions ordinarily escaped. Since it was known that the bright red usually used was vermilion (mercuric sulphide) the conclusion was fairly obvious that the lack of eruption in the red portions was due to the protective quality of the mercuric ion.
The accentuation of