CORRESPONDENCE--LOUIS SCHWARTZ 317 protects the hands from the dye, ammonia, and other compounds in the dye. Many operators do not use gloves when giving shampoos and other non-staining possible irritants. He "believes" that it is only a question of time before continuous use by any one person at home will result in increasing the number of those who are sensitive to paraphenylenediamine and allied compounds. With this observation I cannot entirely disagree because it is possible that by the continued use of any substance--even strawberries, fish, and tomatoes --more people will be sensitized, but the incidence of sensitization today from paraphenylenediamine is so low--1 to 40,000, or less--that even a doubling of this incidence would still make paraphenylenediamine hair dyes as they are manufactured, regulated and used today safe for use because an incidence of 1 case of dermatitis in 20,000 is certainly not alarm- ing and is certainly comparable with the incidence of dermatitis from soaps and even articles of food. Dr. Peck does not take into consideration the fact that many people become even more immune (haMened) by con- tinued use and increased exposure and that improvements in manufacture and use of paraphenylenediamine may further take place and cause a lessening of the incidence of dermatitis, as has happened in the case of indelible lipsticks using fluorescent dyes, nail lacquers, and in the case of the cold wave which when it first came out caused a high incidence of dermatitis. As for his quotation from Harry's book as to the desired properties of an ideal hair dye, which takes up the rest of the article on page 127, no one can disagree with the requisites of such an ideal hair dye, but there is no substance to which someone may not become sensitized and there have been no authentic cases of "systemic" poisoning in humans re- ported from paraphenylenediamine when properly used as a hair dye. Paraphenylenediamine answers all the other requirements given by Harry. Paraphenylenediamine hair dyes today are being used by millions of people in the United States and other parts of the world. The incidence of dermatitis from them is so low that casualty companies will insure at low rates those manufacturing and selling the dyes, provided proof is presented that they have been tested by the "prophetic patch test" or one of its modifications, conducted by a recognized dermatologist. Paraphenylenediamine is the most frequently used fur dye, yet the in- cidence of dermatitis from paraphenylenediamine dyed fur has also greatly diminished. A telephone query to the Medical Director of one of the largest manu- facturers of paraphenylenediamine elicited the statement that "they had not had a case of dermatitis from it, among their workers for as far back as he could remember, over 20 years." The United States Government through its Food and Drug Admin- istration has investigated the possible hazard and incidence of dermatitis from paraphenylenediamine hair dyes and permits them to be sold under existing Federal regulations. All the States are doing the same. The proof of the pudding is in the eating. Truly yours, LovIs SCI•WARTz, M.D. LS/as

BOOK REVIEWS POLYVINYLPYRROLIDON, by Walter Reppe, Verlag Chemie, G.M.B.H., Weinheim, Germany, 1954. 72 pages. Price DM 9.80. Polyvinylpyrrolidone (PVP) orig- inated in Germany where it gained considerable prominence during the second World War, as a blood plasma substitute or extender. In combination with a solution of several inorganic salts, isotonic with blood, it was introduced by the Farbenfabriken Bayer in Lever- kusen under the designation of "Periston" about ten years ago. Enormous quantities of it were used by the German army. Since information as to the use- fulness of PVP and as to its produc- tion methods became available out- side of Germany following the seizure of patents and the publica- tion of pertinent laboratory and manufacturing data, the author's monograph is intended, among other things, to stress the German origin of a subsequent contribution to this development. The booklet gives detailed infor- mation concerning the several steps in the synthesis of PVP on a manu- facturing scale. Other chapters furnish a wealth of physical, chemi- cal, and analytical data. Consider- able space is devoted, of course, to the pharmacological and clinical studies on PVP while compara- tively little is said concerning its application in cosmetics. Inciden- tally, mention is made of Shelansky's work on the PVP-iodine complex in which iodine appears to be substan- tially detoxified. The extensive bibliography with its 283 literature references appears to cover the several aspects of the subject with noteworthy thorough- ness.--E. G. KLAk•4ASN, Lehn & Fink Products Corp. HANDBOOK OF COSMETIC MATE- k•AnS, by Leon Greenberg and David Lester, with a chapter by H. W. Haggard. Interscience Pub- lishers, Inc., New York 1, N.Y., 1954. 455 pages, 6 X 9 inches, no illustrations or index. Price $12.50. The authors claim to have gone over some 4000 articles or books of which they quote a bibliography of 2734 entries. The literature does in- clude some references to 1950, with few references in 1949 and 1950 most of them are prior to 1940. This is the culmination of extensive studies on the dermatological properties of cosmetic materials at Yale Univer- sity, sponsored by the T. G. A. In so vast a reference list one would expect to see mentioned all the accepted literature of the cos- metic industry. Of the cosmetic books mentioned, one finds Cerbe- laud, Chilson, Goodman, Harry, Poucher, Wall, and some Winter. "The Chemistry and Manufacture of Cosmetics," by deNavarre, and Winter's classic encyclopedic "hand- book" are missed. On the essential oils, Gildemeister and Hoffman and Parry are given but not Cola, Finn- more, or Guenther (at least four volumes of Guenther's "The Essen- tial Oils" appeared before the end of 1950). The fine work of Patterson and Hall on essential oils presented before a Toilet Goods Association 318