32 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS and this, in turn, is preferred to the ß stronger alkalies such as sodium hydroxide. Waving with metcap- tan is remarkably kind to the hair. ß Despite recent publicity, waving with thioglycolic or other metcap- tans can be done with complete safety. As a matter of fact, it is a testimonial to cold waving with thioglycolic acid that only two ad- verse articles have been published, and both of these are open to con- siderable criticism. Answers have been made and are being made to these two articles elsewhere. It is sufficient to say here that statistics prove the safety of mercaptans in cosmetics. With both depilatories and cold waving there are tremendous expanding markets yet the insurance rates on both products have been constantly decreased. In conclusion, it should be pointed out that these two commercial uses of mercaptans in cosmetics will un- doubtedly serve not only to stimu- late interest in the use of them in other cosmetics but also--more important--to remove the barrier of prejudice against many other chemical substances which we in the cosmetic industry may have thought of no value because they of them- selves displeased our aesthetic senses. It was as a result of the two dis- coveries discussed here that research brought thioglycolic acid (and other mercaptans) from the status of laboratory curiosities to full scale commercial production. New uses for these products are now being evaluated and thus the cosmetic industry once again indirectly affects the well-being of other in- dustries. REFERENCES CITED 1. Fischer and Penzoldt, dnn., 239, 131 (1887). 2. Beckmann, Pharm. Zentra/halle, 37, 557 (1896). 3. Nencki and Sieber, Monatsh. 10, 526 (1889) Ber., 34, 201 (1901). 4. Nencki, Ber., 25, 512c (1892). 5. Zeise, dnn., 11, 1 (1834). 6. 'Ball and Haines, Chem. Eng. News, 24, 2765 (1946). 7. Koeune, Mfg. _Perf., Feb., 1937, 158. 8. Consumers Reports, No. 211 Aug., 1946.

THE PIGMENT MELANIN OF THE SKIN AND HAIR* By S2•4uv,•, M. PF, CK, M.D. New York, N.Y. IN THE higher vertebrates, especially in man, most of the mela- notic pigment is to be found in the ectordermal elements of the skin, where it plays a much more impor- tant role than the mesodermal pig- ment. The pigment building cells (melanoblasts) of the epidermis are the ordinary basal cells, sometimes cells lying directly above them, and cells living at about the basal cell level but showing dendritic proc- esses. Melanoblasts are also found in the hair matrix cells of the bulb, in the epidermal hair sheets, the epi- dermal parts of the sebaceous glands, the excretory. ducts of the sweat and sebaceous glands and in certain mucous membranes. With the paper of Kolliker in 1860 there began a controversy that lasted for many years as to whether the epidermis built its own pigment or whether it obtained this pigment from the curls. According to Kol- liker, Aebi, Halpern, Riehl and Karg (1860 to 1891), cells from the cutis (connective tissue cells or leukocytes) filled with pigment wandered up to the epidermis and gave up their melanin to it (1). Ehrmann (2), in his comprehensive * Presented at the December 6, 1946, Meeting, New York City. monograph on pigment in 1896, con- cluded that melanin was formed in special cells, "melanoblasts," which were not identical with leukocytes, connective tissue cells or epidermal elements. These melanoblasts were of mesodermal origin, and they were capable of wandering into the epi- dermis and functioning there. By means of their dendrites they trans- ferred their pigment to the other epidermal cells. I•oeb, Mertsching, Garcia, Schwalbe and Post (3), in a series of papers (all published before 1900) based on experimental and embryologic studies, disagreed with the authors mentioned, and main- rained that the epidermis was capable of building its own pigment without any help from roesoder- really derived elements. Investigation of the embryology of formation of pigment in the skin of the higher vertebrates, including man, by Meirowsky (4), Wietipg and Hamdi (5), Adachi (6), Bloch (7), Miescher (8), Steiner- Wourlisch (9), Dawson (10) and others during the last thirty years has shown that this formation was autochthonous in the epidermis. They all agreed that from the earli- est embryohal life the ectodermal 33