Synovial Fluid Mucin.

Synovial mucin, the characteristic component of synovial fluid, was first isolated in 1846 by Frerichs (1846), who precipitated it from joint fluid by addition of. acetic acid. Its high viscosity and peculiar chemical composition made it a subject of much interest. Frerichs realized that it was a complex of protein and carbohydrate components, but little -additional information was added until the 1930's, when hyaluronic acid, the carbohydrate component, was isolated and more closely studied. Even so, much. confusion still exists concerning both the constitution of hyaluronic acid and the type of linkage by which it can unite with protein. The -question is still unsettled whether connective tissue mucins found in different situations in the body are all similar or whether there are a great variety ofmucins differing one from another in the character -of their protein groups or even also in the hyaluronic acids they contain. With regard to the physiolQgical role of the imucins, we have hardly got beyond the realm of speculation, and their actual relation to disease processes is therefore equally obscure. Within recent years several different lines of approach have been made towards these various problems, particularly as regards the synovial mucin of joints, and it is my intention to describe 'to you briefly what progress has been made towards an understanding of the chemical and physiological fields.