There is scarcely any subject of so much importance to the bleacher, textile colourist or textile manufacturer as the structure and chemistry of the cotton fibre with which he has to deal. By the term chemistry we mean t only the composition of the fibre substance itself, but also the reactions it is capable of undergoing when brought into contact with various chemical substances-acids, alkalies, salts, etc. These reactions have a very important bearing on the operations of bleaching and dyeing of cotton fabrics. A few words on vegetable textile fibres in general may be of interest. Fibres are met with in connection with plants in three ways.