SECRETION, in the animal economy, the separation of some fluid mixed with the blood by means of the glands. See the article GLAND.—In the bodies of animals we observe a great number of juices of different natures, viz. the blood, lymph, saliva, stomach-liquor, intestinal juices, pancreatic juice, bile, urine, &c. and the blood is the general source of all. See the articles BLOOD, LYMPH, SALIVA, &c.