Page:The American Cyclopædia (1879) Volume VII.djvu/851

 GLAMORGANSHIRE GLAMORGANSHIRE, a S. county of Wales, bordering on Caermarthenshire, Brecknock- shire, Monmouthshire, the Severn, and Bris- tol channel; area, 855 sq. m. ; pop. in 1871, 396,010. The northern portion is mountain- ous, but the southern is level and fertile. The principal crops are wheat, barley, oats, beans, peas, vetches, and turnips. The horned cattle are of superior quality, and in the mountain districts great numbers of sheep and ponies are reared. Glamorganshire is famous for its coal and iron mines. In the neighborhood of Merthyr-Tydvil the iron works are on a gigan- tic scale ; within a small circuit are more than 60 blast furnaces, some of which have 6,000 workmen. Vast quantities of coal and iron are annually exported from Cardiff. This county has also some woollen manufactories, and numerous canals and railways. The prin- cipal rivers are the Rhymney, the Taff, and the Tawe. The chief towns are Cardiff, the capi- tal, Merthyr-Tydvil, Swansea, and Neath. GLAND (Lat. glans, an acorn), in anatomy, the general name of a variety of organs whose functions are to elaborate the various products of secretion from the blood, to perform certain offices connected with absorption and assimila- tion, and to assist in preparing and maintain- ing the circulating fluid in a normal condition. Of the first class of glands the liver and the salivary glands are examples, of the second the mesenteric and lymphatic glands, and of the third the spleen. The true secreting glands are of various form, size, and structure, but are all constructed with special reference to the arrangement of the nucleated and epithelial cells and tubes or cavities which enter into their texture ; their products are poured forth either on the outer surface of the body, or into some cavity or canal communicating externally, and the cells which effect the separation of their special secretions from the blood are generally in the relation of epithelium cells to the inversions of the skin or mucous mem- branes that form the greater part of their follicles or tubuli. These cells generally min- ister to the act of secretion by absorbing from the blood its watery and saline ingredients, which they afterward exhale in the requisite proportions, and by generating at the same time a peculiar ingredient by their own pow- ers of assimilation ; thus producing a secreted fluid different in composition from the blood from which it was derived. The great ma- jority of glands provided with ducts may be divided into three groups, according to the modes in which the cell-containing tubes are arranged: 1, the simple tubular glands, like the follicles of the stomach and intestines, which seem to be mere depressions in the mucous membrane, or elongated vesicles lined with secreting cells; 2, the aggregated or conglomerate glands, in which a number of follicles are grouped into lobules, and these again into lobes joined by loose areolar tissue, like the salivary, mammary, pancreatic, pros- GLAND 835 tate, and lachrymal glands, and also the liv- er ; 3, the convolu- ted tubular glands, as the perspirato- ry and sebaceous glands ending in dilatations, cul-de- sacs, or loops. In all a large extent Ultimate Glandular Follicles. of Secreting Surface a. Membrane of the follicle. 6. iq nnrlrpd in a amnll Layer of epithelium lining the compass ; while one follicle, seen in profile, c. Sur- face of epithelium cells, lining the whole interior of the fol- licle. end of the gland and duct opens on a free surface, the opposite end is closed, and has no direct com- munication with blood vessels or other canals. The glandular organs have been divided into two classes, according as their product is ex- creinentitious and to be cast off, or to be used Mucous Glandule, from the Cavity of the Mouth. a. Investment of areolar tissue. 6. Excretory duct, c, c. Secreting follicles, d. Branches of the excretory duct within the system ; the former are called more properly excretory glands, and include the kid- neys, and those which supply the cutaneous and pulmonary transpiration and the peculiar faecal matters of the lower part of the intes- tinal canal ; the true secretory glands are the gastric, salivary, mammary, sebaceous, mucous, lachrymal, Brunner's, and the pancreas. The kidneys, liver, mammary glands (secreting re- spectively urine, bile, and milk), and the pan- creas are described under their proper titles; the salivary and gastric glands are noticed under DIGESTION ; the sebaceous, cernminous, odoriferous, and sudoriparous glands (secreting the oily, waxy, odorous, and perspiratory mat- ters of the surface), are treated in the article SKIN; the follicles of Lieberkuhn (in the small intestine), Brunner's glands in the duodenum, and the solitary glands most numerous in the