230 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS and homocystine. It is not sur- prising, therefore, by virtue of their sulfhydryl group content, that salts of thioglycolic acid should prove to be of low systemic toxicity. In- deed, the toxic actions of heavy metals, including arsenic, may be due larg61y to their combination with the sulfhydryl groups of the proteins of the tissues with the for- mation of mercaptides. In this connection, one may point to the success of dimercaprol, usually re- ferred to as BAL, a dimercaptopro- panol, in the treatment of heavy metal poisoning. Conversely, the capacity for metal mercaptide for- mation of sulfhydryl groups, when present in large excess, may result in unfavorable toxic effects by com- bination with the metal ions of the metallo-protein enzyme systems. Dermatologic reactions attributed to cold wave lotions were first re- ported in 1944. Since that time, additional reports of both cutaneous and systemic effects of waving lo- tions, as well as the ingredients thereof, have appeared. It is quite evident that there exists a great diversity of opinion concerning the effects of waving lotions and their ingredients. This is due primarily to the use of a variety of materials, comprising in some instances the waving lotions themselves, and in others, the use of isolated ingredi- ents to the use of various concen- trations and pH of the waving mate- rials to the employment of a variety of methods of testing to a variation in the selection of test subjects, and to the inadequate testing of subjects who are sus- pected of showing systemic .toxic manifestations. It is axiomatic that differences in results reported by various observers should stem from some difference in the experi- mental approach, yet careful analy- sis of some of the published data fails to disclose adequate reasons for such divergence. For example, Beek (2), using a 6 per cent solu- tion of thioglycolic acid neutralized with ammonium hydroxide to a pH of 9.0, reported an incidence of skin reaction far in excess of that which we have found in an extensive and closely controlled investigation. From a study conducted on five female patients who had in common a history of occupational or cosmetic contact with cold wave lotions, Cot- ter (3) came to the conclusions that the cold wave lotions were respon- sible for the dermatologic and clini- cal findings,"... because, it had been possible to demonstrate their lesions in the laboratory." On pe- rusal of the case histories which were published in detail, it becomes evident that despite the common denominator of contact with cold wave lotions, there are many other and compelling reasons why the author was not justified in draw- ing the inference of causal rela- tionship between contact and clini- cal findings. Editorial and advis- ory notes appearing in medical and lay periodicals show a diver- sity of opinion on the effects of cold wave preparations, some warn- ing quixotically against the use of these agents, others taking the op-

COLD WAVE LOTIONS CUTANEOUS AND SYSTEMIC EFFECTS 231 posite stand. Those articles which condemn the cold wave process rely primarily upon the published ar- ticles of Howell (4) and Cotter, and in so commenting, add to the list of adverse literature on the subject, without actually contribut- ing new data. Mention is infre- quently made of the method em- ployed or of the chemical composi- tion or concentration of the material tested, or whether a solution of am- monium thioglycolate or a commer- cial wave lotion had been used. This report partially reported elsewhere (5) concerns the effects of certain cold wave lotions on the health of 1200 persons who volunteered for tests of these prod- ucts. In order that the results might have practical value, the material employed in these tests was a commercial home cold wave preparation in wide popular use, rather than an empirical solution of a salt of thioglycolic acid. In addition, many other impor- tant considerations of a chemical nature dictated the use of an actual cold wave preparation. Among the constituents of cold wave lotions are ammonium hydroxide, thio- glycolic acid, and a wetting agent. The ammonia, which is a gas at room temperature, is dissolved in water to form ammonium hydroxide, which has a high vapor pressure. From its water solution ammonia volatilizes rapidly, especially under conditions of good exposure af- forded during the cold wave proc- ess. The thioglycolate, likewise, is very susceptible to atmospheric oxidation, being oxidized to a rather inert substance, diammonium di- thioglycolate, under conditions of usage exposure. For these reasons, the waving lo- tion which comes in contact with the scalp is very rapidly converted into a relatively inactive material. The wetting agent which is present, while causing more intimate contact with the skin, also causes the solu- tion to spread over the skin surface in a very thin film. This increases the exposure of the lotion to the air, enhancing volatilization of the am- monia and oxidation of the thio- glycolate. On the other hand, the cold wave lotion in contact with the hair, under actual hair waving conditions, does not change so rap- idly because each tress is coiled, de- laying the decomposition of the cold wave solutions, ex:ept on the outer- most surface. Because the chemical reactivity of cold wave solutions is affected by the concentration of am- monia and thioglycolate, by the pH, and by the type and amount of wetting agent used, the results ob- tained in our work apply only to the waving lotion we used. A seri•s of studies was performed on normal subjects and on subjects with various skin diseases on persons with no known contact with cold wave solutions and on many in intimate and prolonged contact--- in a successful attempt to delineate fully and critically the part, played by cold wave lotions on the health of that part of the population most likely to come in contact with these materials. Recent experience in