Tears

Tears usually consist of pure water, with saline traces; but in cases of poisoning may show the poison, and in diabetes become saccharine like the other secretions. The lachrymal apparatus is described at EYE, Vol. IV. p. 509. Serving normally to moisten eyeballs, interior eyelids, and nose, they are regularly secreted in normal quantities, and disappear by the duct into the nose. Where there is spasmodic contraction of the muscles about the eye, as in fits of coughing, yawning, or immoderate laughter, the tears are squeezed out from the eyelids and run down the cheeks. In man they are also the natural outlets of strong emotion, and are secreted in greatly increased quantity; they much more constantly accompany crises of fear, anxiety, grief, affection, and keen joy than physical pain. Old age is comparatively tearless. Some animals, especially deer, are credited with weeping tears of grief. Darwin says few animals shed tears at all; he failed to notice weeping in monkeys, but records Emerson Tennent's opinion that elephants weep with sorrow, as supported by the keepers of tame elephants. See Darwin's Expression of the Emotions (1873).