RT Journal T1 ÉTudes sur les nævi pigmentaires de la peau humaine (melanoblastomes bénins). JF Journal of the American Medical Association JO Journal of the American Medical Association YR 1929 FD February 16 VO 92 IS 7 SP 583 OP 583 DO 10.1001/jama.1929.02700330067038 UL http://dx.doi.org/10.1001/jama.1929.02700330067038 AB Some of the author's first published results from working with the dermatologist Bruno Bloch of Zurich, in 1918, appeared in the British Journal of Dermatology and Syphilis in 1920, and in this monograph they are elaborated. They all deal with the method which bears Bloch's name of demonstrating microscopically the presence in certain cells of an oxidizing enzyme supposed to be tyrosinase. Use is made of 3, 4 dioxyphenylalanin, a compound with its name now shortened to dopa, and the test has been known now for several years as Bloch's dopareaction. Kissmeyer has studied the nature of the reaction carefully and determined the optimal ph at which it occurs. Applying it to a study of nevi and to many other conditions in which the skin is pigmented, he has accumulated a great deal of evidence that the staining which results in certain cells is specific for epithelial cells, and