Journal of Applied Microscopy. 455 



tary muscle cells, and in fortunate sections may be seen to give off short lateral 

 twigs, terminating in fine granules in the muscle cells. 



The same distinction is made as to the character of the medullated and non- 

 medullated fibers of the dura mater. The medullated fibrils, after branching at 

 the nodes of Ranvier, terminate in long varicose fibrils, extending through 

 several fields of the microscope. These fibrils interlace, but do not anastomose. 

 The sympathetic nerves form perivascular plexuses comparable with those found 

 in other parts of the body. 



Technique. — The animal was anesthetized, the canula inserted cerebralward 

 in a carotid, and enough one per cent, methylen blue, made up in normal salt, 

 injected to tinge the ear and eye of the side injected. After thirty or forty-five 

 minutes, the brain and cervical cord were exposed with the least injury possible 

 Xb the dura. 



After removal, the brain was exposed to the air until the nerve fibers were 

 stained, and pieces of the cortex were cut off with curved scissors and crushed 

 under a cover-glass until the brain tissue was pressed away from the pia mater. 



E. M. B. 



Obersteiner, Heinrich. The Maintenance of Touch sensations, which are perceived 



the Equilibrium as a Function of the Cen- by means of nerves from the joints, ten- 



tral Nervous System. Am. Nat. 33: ^n- , , , . , 



■xzQ i8qq. dons, and muscles, sensations from the 



labyrinth of the ear, and optic sensa- 

 tions, react through the brain upon the muscular system to produce equilibrium. 

 As a rule, we are unconscious of many of these sensations. 



A parallelism is found between the size of the cerebellum and the delicacy 

 of the muscular coordination. In mammals and birds, where very sensitive and 

 complicated muscular action is required to maintain equilibrium in standing, 

 running, or flying, the cerebellum is relatively large, and its surface is increased 

 by many deep furrows. In amphibia and many reptiles which have merely 

 crawling or jumping motions, the cerebellum is reduced to a mere ridge. 



If the cerebellum of an animal is wounded badly, or if a portion of it is 

 extirpated, there is no proper regulation of muscular contraction, and there is a 

 decided disturbance of the equilibrium, although the intelligence of the animal is 

 not interfered with. He believes that sensations are received in the cerebellum, 

 and are there combined into a resultant nervous impulse which modifies the 

 movements incited by the cerebrum in such a way that the desired coordina- 

 tion is attained. e. m. b. 



Weil, Richard. An Anomaly in the Internal The trochlear nerve in a human foetus 

 Course of the Trochlear Nerve. Jour. Comp. ^f between eight and nine months de- 

 Neur. 9: 35-37, i pi-, 1899. ° 



velopment was found to originate 



normally in the floor of the Sylvian aqueduct, but instead of making its exit at 

 the level of the decussation in the posterior medullary velum, it turns and runs 

 forwards and outwards, traversing the velum and the posterior quadrigeminal 

 bodies, and makes its exit between the posterior quadrigemina and the inferior 

 fillet. Although this does not correspond with any stage in normal development, it 

 is suggested that it may be taken as a clue to the original course of the nerve. 



