Material formed by a gland (see GLANDS) as the result of its activity. For example, saliva is the secretion of the salivary glands; gastric juice that of the glands in the stomach wall; bile that of the liver. Some secretions consist apparently of waste material which is of no further use in the chemistry of the body. These secretions are often spoken of as excretions: for example, URINE and sweat – see PERSPIRATION. (For further details, see ENDOCRINE GLANDS, and also under the headings of the various organs.)