If we exclude from consideration the relaxations of tissue that mucous membranes suffer from inflammation and oedema, and the solutions which take place during and after exudative processes, we shall still find conditions occurring on some mucous membranes, particularly in the stomach, oesophagus, and intestinal canal, which differ entirely from the former, both in their causes and in their anatomical characters, - conditions which are included within the term softening in its restricted sense: they will be found treated of amongst the diseases of the apparatus in which they occur.