102 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS may use up much of the small amount of emulsifier present and, worse yet, convert it to a product which is insoluble and water repellent. This can seriously affect the stability of the emulsion or even break it. There is one other interesting effect, in creams and lotions, of the EDTA salts. Studies have shown that they sequester and chelate the nutrient minerals which are required for the growth of bacteria and micro6rgan- isms so that these mie'roSrganisms in'many cases literally starwe'and can- not continue growth. For this reason they have a definite preserving, effect. It is well known that iron darkens deodorant and an•iperspirant creams with their acid pH. One pays a premium for iron-free raw materials such as aluminum trichloride. The EDTA salts are especially active in chelating iron under these acid conditions. Their use to scavenge the last traces of iron which may cause you trouble is therefore of compelling interest. The purest commercial form of EDTA is 99 per cent pure and is actually running closer to 99• with the other half per cent mostly water and sodium sulfate. The product is an odorless and colorless powder. Also available are the di-, tri-, and tetrasodium salts which are frequently more convenient to use than is the acid. In distilled water, the acid has a solubility of about 0.02 per cent. This doesn't seem like very much but it is 200 parts per million and that is frequently enough to more than tie up the traces of iron and copper which may be present in a product. The solubility increases as you go from the mono- to the di-, to the tri-, and to the tetrasodium salt. We understand, of course, that in many cases sodium salts in your product are not desirable and in those cases it is relatively easy to use the free EDTA and make the salt of any metal or amine desired. Finally, I would like to mention some other interesting applications of these sal•s which are not related to the cosmetic field. In Florida, for years they have had trouble with iron chlorosis which is due to a shortage of available iron in the soil. They can add all of the common iron salts they want to the soil and the tree is still not able to assimilate it. How- ever, the addition of only a few ounces of the iron salt of ethylenediamine tetraacetic acid will show up in improvement within a few days. We do not understand the mechanism whereby the tree is able to extract the iron from the complex nor do we know whether or not the iron complex itself is first absorbed and then the iron removed or whether the absorp- tion is of the iron only. It has been found that many soils actually con- tain iron but that it is unavailable to the plants. The addition of EDTA or of its sodium salt to these soils will chelate iron present and make it available to plants. There has been considerable additional work upon cotton and corn and this work indicates that these complexes will be economically useful for these crops, too. Some work has been done with

CONSUMER TESTING AS A GUIDE FOR TECHNICAL RESEARCH 103 other trace elements such as manganese. However, since iron is chelated more readily, the addition of the manganese complex only assists in the pickup of more iron as the manganese is replaced by iron in the complex and carried to the plants. Another new application is the use of these agents in the manufacture of cold rubber which is exceedingly sensitive to the least traces of some polyvalent metal ions. There has been yet another application reported recently which we hope we will not have to use. The EDTA salts are among the best agents for the removal of surface radioactive contamination. In case of atom bombing, large areas of surface such as of buildings, walks, pavements, automobile bodies, etc., would have to be decontaminated. The use of EDTA as a component of decontaminating detergents should add sub- stantially to the rapidity and thoroughness of decontamination. CONSUMER TESTING AS A GUIDE FOR TECHNICAL RESEARCH* By NORMAN H. ISHLER Central Laboratories, General Foods Corp., Hoboken, N.y. AT FIRST GLANCE the cosmetic industry may seem to have very little in common with the food industry. However, after a little thought on the subject a number of common interests begin to appear. Technically the two industries deal with many of the same problems. They are both concerned with emulsions, colors, fats, oils, and starches. They both, of ne- cessity, must be concerned with the toxicity of their products. A par- ticularly important common ground is that of odor or aroma. All of these things are building blocks of which both food and cosmetic products are built. If the ingredients are the building blocks then the products themselves must be considered as the complete structure. In both foods and cos- metics, the common objective is to satisfy the ultimate consumer. The cosmetologist strives to satisfy his customers by improving their appear- ance, aroma, or touch. How effective his results are when properly used is apparent to all of us whose blood pressure rises with a faint trace of per- fume from the girl a few feet away, or whose head turns automatically to the rear from time to time while walking down the street. * Presented at the December 10, 1953, Meeting, New York City.