Page:The New International Encyclopædia 1st ed. v. 06.djvu/291

* DIGESTION. 247 DIGHTON ROCK. matters arc allowod to pass forward with facil- ity, while regurgitation is impossihle. (For anatomical details regarding the large intestine, we may refer to the articles .Xlimextary System ; C.a:cuM : and Colon.) The contents of the large intestine diller very materially from those which we have been considering in the last ])anigraph, and constitute the f.Toes. They are more solid and homogeneous, and are often molded into a defuiito shape by the cells of tlie colon. The only essential change which the contents undergo in this part of their course is that they increase as they pass onward in solidity, in consequence of the absorption of lluid from them by the mu- cous membrane. They are propelled forward into the rectum by the vermicular action which has been already described. Here they accumulate, being prevented from escaping by the contraction of the sphincter muscle — a liand of strong nuiscu- lar fibres surrounding and closing the gut at its lower extremity. The act of defecation, or of ex- pulsion of the fopces from the rectum, is effected partly by the muscular fibres of that part of the intestine which are stimulated to contraction by a certain degree of distention, and which are to a certain extent under the influence of the will, and partly by the simultaneous contractions of the abdominal muscles and of the diaphragm, which, by reducing the anteroposterior and transverse diameters of the abdominal cavity, compress the intestinal canal in such a manner as greatly to assist the expulsive action of the rectum. These forces, or some of them (for usu- ally the detrusive action of the muscular fibres of the rectum is sufficient K overcome the passive contraction of the sphincter, and the act of def- ecation is the result. See F.iicEs. (8) The absorption of the chyle forms the com- pletion of the digestive act. The coats of the intestines contain two perfectly distinct sets of vessels — one through which blood circulates, and the other containing a milky or transparent fluid, chyle, or lymph, which, after a somewhat circuitous route, is poured into the blood. We have already referred to the fact that fluids are ab-sorbed from the stomach and intestine by the veins and capillaries of the mucous membrane: we now proceed to notice the mode in which the vessels of the second kind — the lacteals — act as absorbing agents. The lacteals are merely a por- tion of the great lymphatic system of the body, which will he described in a future article. (See LvsiriiATJcs.) They commence, as has been previously mentioned, in the villi, and possibly also in the intervening mucous membrane; and when an animal is killed while the digestive process is going on, they have, in consequence of their being distended with chyle, the peculiar white or milky appearance which procured for them their name of rasa lactra. from their dis- coverer. .sellius. in lfi22. They pass in great numbers, and in a reticulated arrangement, be- tween the layers of the mesentery, the portion of peritoneum (q.v. ) which sirrounds the gut and retains it in its proper position. After passing through the mesenteric glands, where their eon- tents seem to become more highly organized, they make their way to the right side of the aorta in the lumbar region, where they finally dis- charge themselves into an elongated pouch, termed the rerrptnruhint rhj/Ii. From this pouch the thoracic duct, containing the chyle, passes upward alon? the vertebral column till it reaches the level of the arch of the aorta, be- hind which it runs to the left side and discharges its contents into the subclavian vein, close to its origin with the internal jugular, its orifice l>eing protected by two valves. The nature of these contents has been already described in the article Chyle. This chyle is in reality incipient blood, which has been formed, as we have already seen, from the food, and has been absorbed from the intestine by the lacteals. We have now- traced it to its entrance into the general circulation, and it only remains for it to pass, in conjunction with the venous blood with which it is mixed,, through the lungs, in order to be converted into new and perfect arterial blood, fit for the highest processes of organization. DIGGER. A collective term, without ethnic significance, formerly applied to a number of In- dian tribes in central California and the adjacent portion of Nevada, probably from their root-dig- ging habit or from their 'dugout' dwellings. See SHo.si!oxr.x Stock. DIGGER-WASP. See Mud- Wasp. DIGGES, digz. Sir Dudley (1583-16.30). An English diplomatist and jurist. He was born at Barham. Kent, the son of Thomas, and gradu- ated at Oxford in 1601. In 1618 he went to Rus- sia, and in 1620 to Holland as special ambassa- dor, but later fell into disfavor through his inde- pendent opinions. He was author of Ki/ihtu nnd Privileges of Ihe Subject (1642) and The Corn- pleat Ambansador (1655). He .sat in Parliament for Tewkesburv from 1624 to 1626, and for Kent in 1628. His 'son Dn)LEY (161.3-43). a devoted royalist, was the author of The Unlawfulnesse of Subject.i Taking up Arjns Against Their Saver- aignc (1643). DIGGES, Leonard (? — c.lSTl). An English mathematician. He was educated at Oxford and was the author of Tectonieon (1556|. (m measur- ing land, etc.; Pantometria : A Geometrical Prac- tise (1571) : and .4 Prognostication Everlasting (1553-56). an astrological work. DIGGES, Thomas (?— 1595). An English mathematician, the son of Leonard. He was edu- cated at Cambridge and entered Parliament in 1572. He constructed the alterations and forti- fications of Dover Harbor, served in the Low Countries in 1593-94, and was interested in a search for the dominions of the great 'Cam of Cathaia,' in the Antarctic seas. He edited his father's Pantometria and a great many treatises on science and military engineering. DIG'GORY. . awkward servant, in fiold- smith's She Stoops to Conquer. He begs Hard- castle not to upset his gravity during the ordeal of waiting on table by telling the story of the "Ould C.rouse in the Gun-Poom." DIGHTON ROCK. A greenstone boulder near Dighton. M;iss.. bearing an inscription which has been inuch discussed by antiqiiarians. A draw- ing of the inscription was made by Dr. Danforth in' 1680. another bv Cotton M.ither in 1712, and others in 1730. '1768. 1788. 1700. 1807. and 1812. In 18.30 the Rhode Island Historical So- ciety made a careful study of the inscription, which was interpreted by Rafn (Antiquitates Americana;, Copenhagen, 1845, pp. 357-60) as Xorse. The rock was rei'xamined by Dr. Hoffman for the Bureau of Ethnologv' in 1886, and the inscription was reproduced and discussed by