MEDULLA OBLONGATA. 



629 



transit of impulses, while the felt-work of fine fibres in the gray 

 part can also conduct impulses in all directions. Though the 

 readiness of transit is much less along the thin-fibred network than 

 via the direct medullated routes, the complexity of paths and the 



FIG. 245. 



Diagram of Brain and Medulla Oblongata. (Cleland.) a, Spinal cord ; 

 6, 6, Cerebellum divided, and, above it, the valve of Vieussens partially di- 

 vided ; c, Corpora quadrigemina ; d, d, Optic thalami; e, pineal body; /,/, 

 Corpora striata ; g, g, Cerebral hemispheres in section ; h, Corpus callosum ; 

 i, Fornix ; I, I, Lateral ventricles ; 3, Third ventricle ; 4, Fourth ventricle ; 

 5, Fifth ventricle, bounded on each side by septum lucidum. 



variety of directions in which they lead, is much greater in the 

 gray than the white substance. It is by means of the gray sub- 

 stance that the two lateral parts of the medulla are so nearly 



