JOURNAL OF THE SOCIETY very marked reduction in underarm odour, and perspiration odour in general. This effect persisted for some eighteen hours or more. It had similar good effect in controlling halitosis caused by decaying teeth or metabolic disorder, or due to smoking or alcoholic beverages. Equally good results were claimed in the reduction or disappearance of menstrual and foot odours. Like so many earlier investigators West- cott used a proprietary brand of material, the nature of which is not d•sclosed beyond the fact that it is described as "specially prepared chlorophyllins" Not unnaturally, the conception that simple oral administration of tablets could reduce or suppress all body odours has aroused great in- terest. In the U.S.A. and Canada several firms are now marketing tablets containing the particular chlorophyllin preparation used by Westcott, and these tablets are find- ing a large sale. Interest has been no. less marked in this country and on the Continent. Within the past few months, Dijkstra in Holland has• published a lengthy series of con- firmatory data, from which he con- cludes that chlorophyll may be re- garded as a universal deodorant having a distinct reducing effect on all body odours. He suggests that its action is of a chemical nature and connected with an effect on in- terchange of gases in the tissues, and reduction in total gas production. Here the speaker outlined the possibilities of deodorization being caused by reduction, the chloro- 192 OF COSMETIC CHEMISTS phyllin liberated from its sodium or potassium salts by the stomach acids being itself oxidised. Alternatively, he added, the chlorophyllin may catalyse oxidation of odorous materials, perhaps by forming a loose combination with oxygen and parting with the latter at the sites of action. On the whole, it would seem that mild oxidation, rather than reduction, would be more likely to have a deodorizing effect, particu- larly on sulphur compounds. Some observations were next de- voted to the use of chlorophylis and chlorophyllins in household deodor- ant preparations, where they are usually found in the company of formaldehyde and/or perfumery materials. The speaker concluded his re- marks} with a summary of the exist- ing methods of standardisation of chlorophyll derivatives. In particular he emphasised the need for a really reliable method of standardising chlorophyllins and ex- pressed doubt as to the validity of the ultra-violet absorption methods that have been proposed. An animated di,qcussion followed, much of it being directed to the con- sideration of chlorophyll as a per- sonal deodorant. Among those who joined in the discussion were the speaker, Miss Perry, Drs. Marriott and Middleton and Messrs. Dead- man, Pickthall, Dobson and Wells. A vote of thanks to Dr. Mitchell, proposed from the body of the hall by Dr. R. H. Marriott, was. unani- mously passed by the meeting.

STABILITY OF COSMETIC By W•LL•AM The question of the stability of an emulsion is one of great import- ance to cosmetic chemists. To men- tion just a few cosmetic products which involve the formation of emul- sions in their manufacture is suffi- cient to emphasise this importance. Such cosmetic items include creams of many types, lotions, clouding agents, powder suspensions, "sol- uble" perfume oils, antiperspirant creams, shaving creams, hair dress- ings, vitamin and hormone prepara- tions, and other products. One of the most important features of the development of a new cos- inetic is the matter of its stability and shelf life. Not only must it show the performance •[nd have the attractive appearance and scent necessary for its success, but it must retain these properties until pur- chased by the consumer. In the case of cosmetics it is usual that stability is required over a period of months and often years. There are several ways in which an emulsion may be unstable, and one or more of the changes under- gone by emulsions may be of im- portance in any particular product. The object of this paper is to de- scribe some of these types of in- stability, and to suggest ways of * Colburn Laboratories, Inc., Chicago• EMULSIONS COLmJRN* testing the stability of emulsified products in the laboratory. There is no generally accepted definition of the term "stability" as applied to emulsions. It is obvious that an emulsion sufficiently stable for an agricultural spray, which may be used within a few hours after its formation, would require an entirely different order of stability from that expected of a cosmetic emulsion, which generally must remain unchanged over many months. In fact, the easy separation of the oil phase of an emulsion may be highly desirable, as for example in the formation of a continuous oil film in a thin layer of water-emul- sion paint. Cosmetic emulsions generally con- sist of an oil or wax emulsified with art aqueous solution. If the oil phase is dispersed in the aqueous phase, the emulsion is referred to as the oil- in-water type. An example of this type of emulsion is a "milky" permanent waving lotion. Where water droplets are dispersed in a continuous oily phase, as in a cleansing cream, the emulsion is of the water-in-oil type. The two phases of the emulsion are often referred to as the "dispersed" or "internal" phase on the one hand, and as the "continuous" or "external" phase on the other. There is no defi•fte 93