578 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS rives both from surface tension and from static shear rigidity of the thin films. The kinetic frictional resistance of these ioints is often low, allowing easy combing, but their static strength is considerable-in the range of a few milli- grams. The layer thickness, especially for long hair, must be controlled be- cause, in the case of overloading, the hair mass may compact and settle under its own weight. Chemically active hair cosmetics-bleaches, permanent waves and oxidative dyes-increase the material frictional coefficient and the surface roughness of the fibers and thereby reinforce the fiber-fiber interactions. This results in increased body. III. CONCLUSIONS It is possible to assign physical interpretation to a cosmetic term such as hair body which is 1.ogical and self-consistent in scientific meaning and corre- lates with the linguistic use pattern of the word. Furthermore, it is possible to break down the complex body characteristics into fundamental, single parameter, physical factors. The body attributes of hair cosmetics can be studied systematically, by evaluating their effects on these fundamental fac- tors. It is, of course, quite easy to design measurements for directly assessing the influence of cosmetics on the complex phenomena, and we have used such techniques for body determination for some years. Obviously, the present discussion represents a single viewpoint and further discussions by individuals from different areas of the fiber and cosmetic fields would be highly desirable to achieve a consensus on, and a better definition of, these rather important terms. ( Received Junc 3, 1975 )