To the Editor:
—In The Journal of Nov. 30, 1912, p. 1979, the editorial comment on "Mongolian Birthmarks" (!) is so peculiarly inadequate that it can hardly hope to escape correction. To begin with, a great deal of attention is given to observers who have simply reported the occurrence of tnese spots in another race, while no mention is made of the fundamental work of Adaclii, who ten years ago established the exact morphology of these spots. He showed that the Mongolian spot, a blue spot, that occurs most frequently on the sacrum but also on the back and on the extensor surfaces of the extremities, is caused by large pigment cells deep in the corium, while the ordinary pigment that distinguishes races and individuals lies deep in the epidermis. These cells, if in sufficient number, appear blue on the surface much like the pigment of a tattoo mark, and are