Brain

Largest and most important division of the nervous system; made up of the cerebellum, cerebrum, pons varolii, and medulla oblong at a, all situated in the skull, which reaches IMG:content-0598.jpg:[graphic] IMG:content-0599.jpg:[graphic][subsumed] Brahma, from Benares. to the legends, both Sivaite and Vishnuite, he was born of a golden egg, laid upon the breast of the waters of Chaos by the Fig. 1.-Cerebrum-upper surface (Quain): To show, firstly, division into two nearly equal hemispheres by the great median fi ure; secondly, general appearance and apparert ir- regularity of arrangement of the the convolutions and and fi ures; F.L., frontal lobe; O.L., occipital lobe. its highest stage of development in man. In males and females the average weights are respectively ab. 50 and 44 oz., and its proportional weight to that of the body is ab. 1 to 45 in both sexes. The heaviest brain on record was that of Lord Byron, Sigismund became duke of Pru ia 1618; Frederic III. became king of Pru ia 1701. It is now a province of Pru ia; area 15,380 sq. m.; pop., 1890, 2,542,401, without Berlin. IMG:content-0600.jpg:[blocks in formation] This is now known as the "straight-air" plan, and was the early form of the Westing house brake. It was not automatic in case of accident when any car was disconnected from the engine IMG:content-0601.jpg:[subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][ocr errors] Fig. 2.-Under Surface, or Base of Brain: F.L., T.L., O.L., frontal, temporal, and occipital lobes of the cere- brum; cb , cò , cerebellum, the medulla oblong at a lying between its two lobe. Cranial Nerves. 1, olfactory lobe (the nerve of smell); 2, optic nerve (nerve of sight); 3, third or oculo-motor nerve, motor nerve to mo tof the muscles of the eye; 4, fourth or trochlear nerve, motor nerve to the superior oblique muscle of the eye; 5, fifth, tri- geminus, or trifacial, sensory and motor, the large root sensory to the face and eyes, .; the small root, motor to muscles of mastication; 6, sixth or abduce us nerve, to external rects muscle of eye, turns eyeball outward; 7, seventh or facial, motor to muscles of expres- sion; 8, eighth or auditory nerve, sensory for hearing (cochlea) and for equilib. ation (s micircular canals); 9, glo o-pharyngeal, sensory nerve of taste, and motor to some of the muscles of deslutition; 10, pneumogastric, sensory and motor to larynx, lung, heart, and stom- ach; 11, spi al acce ory, motor to muscles of heart (inhibitory) and sterno-mastoid and trapezius; 12, hypoglo al, motor to all the muscles of the tongue: cl, first cervical spinal nerve. it; and that there are localized centers which control these movements, perceive sensations, and are connected with the performance of all mental acts. Yet scores of cases have occurred in which large portions of it have been destroyed by injury or disease without any perceptible effects upon its functions, but lo of some of these usually follow such injury. It is probable that there is some close relation between the number and complexity of its convolutions and the amount of intellectual development. See CEREBELLUM, CEREBRUM, MEDULLA and PONS VAROLII.