GLAND, in anatomy, a term originally ap plied to such beanlike structures as occur all over the body in connection with the lymphatic system; but the meaning has now been extended to embrace any group of secretory cells. Such structures separate from the blood the charac teristic constituents of their various secretions, and in most cases they are arranged in the form of small sacs, with contracted necks or ducts, through which the secretions are poured. Some glands, however, such as the thyroid and the suprarenals, are ductless, and their elabo rated. products must he absorbed by the blood or by the lymph, for which reason they are sometimes called vascular. The liver is the largest glandular organ in the body, and weighs nearly four pounds. On the other hand, the peptic filands of the stomach are of microscopic dimensions, and consist of simple tubular re cesses lined by a secreting cellular membrane, around which the blood circulates. The sali vary, gastric and intestinal glands secrete the various fluids necessary for the digestion of food; while the kidneys and sweat glands are excretory, and pass waste products out of the circulation. Adenalgia and adenitis are terms
applied to pathological conditions of the glands —pain and inflammation in them. The func tions of the ductless or blood glands are im perfectly understood, but the thyroid secretion has a profound influence on the nutrition of the nervous system, the suprarenals determine cer tain blood conditions, while the spleen and lymphatics are largely concerned with the pro duction of the cellular elements of the blood. Of late years extracts of various glandular tissues have been administered in cases of ill ness which appear to depend on defective gland secretion. The treatment has been a brilliant success in rnyxzderna and in cretinism, which result from disease of the thyroid gland.