organs whose specific function is to separate something from the blood (See SECRETION). In structure a gland is a body of secreting cells, a supporting basement membrane, a fine network of blood vessels, a nerve supply and a duct through which the secretion passes. Simple tubular glands are depressions of the mucous membrane, lined with secreting cells, as the glands of the stomach. Some bodies called glands have no duct, as the spleen and the thymus gland; the latter is situated in the front of the chest behind the sternum and partly in the lower part of the neck. It is largest in infants and gradually disappears in adult, or old, persons. It has been claimed that its function is the formation of colorless corpuscles. In hibernating animals it becomes enlarged and is laden with fat, as the time for the winter sleep approaches, and it may help to maintain the temperature and respiration of the body during the period of rest. The thymus of veal and lamb is called neck sweetbread, to distinguish it from the pancreas, or stomach sweetbread. The thyroid gland lies in the throat below the larynx and when enlarged by disease gives rise to "Derbyshire neck" (See GOITER). The liver is the largest gland of the body. In connection with the alimentary canal there are in the mouth, the two parotid, two submaxillary, two sublingual and many buccal glands, whose function is to secrete saliva. The parotids are situated one in front of each ear and are the seat of the disease known as mumps. Sebaceous glands are abundant in those parts of the surface of the body supplied with hair; they are also situated about the entrances to the body, the nose, mouth and ear. These glands are absent from the palms of the hand and soles of the feet, and pour out an oily secretion which keeps the hair and skin soft. Sudoriferous, or sweat, glands are situated in all parts of the surface of the body and are especially abundant in the palms of the hand and soles of the feet. See SKIN; LIVER; PANCREAS; SPLEEN.