252 PRACTICAL HISTOLOGY [XXX11 



In the lateral area of the cord grey and white substance is 

 much intermixed, there is no separate mass representing the 

 anterior cornu, but the cerebellar tract is obvious. 



Ventrally of the bundles of the pyramidal decussation, a 

 somewhat oval mass on either side the pyramid, now nearly 

 complete. 



3. Section just above the pyramidal decussation and 

 below the lower olive. The nucleus of the funiculus gracilis 

 and that of the funiculus cuneatus are larger ; the fibres of the 

 funiculus cuneatus form a shallow horseshoe-shaped mass ; the 

 bulbar root of the 5th is larger. Note : 



Small patches of grey substance with rather large cells 

 stretching into the funiculus cuneatus the accessory nucleus 

 of the funiculus cuneatus ; examine the cells with |rd objective. 

 (The nucleus may be absent immediately above the decussation.) 



The very marked sensory decussation ; bundles of fibres 

 curve from the base of the nuclei of the posterior columns, 

 round the central grey substance, and decussate dorsally of the 

 pyramids. 



The pyramids forming two rather large masses in the ventral 

 region. 



External arcuate fibres ; large fibres taking an oblique 

 course on the surface of the pyramids and the lateral region of 

 the cord, covering the bulbar root of the 5th nerve, and part of 

 the funiculus cuneatus ; fibres may be seen spreading over the 

 bulbar root from the dorsal cerebellar tract. 



On the course of the fibres in the pyramids are small masses of 

 grey substance with fairly conspicuous cells, the nuclei of the external 

 arcuate fibres. 



The accessory lower olive, an elongated mass of grey substance, 

 dorsally of the pyramid, and stretching a short way laterally of the 

 sensory decussation. 



The antero-lateral nucleus, & large group of scattered nerve cells, 

 dorsal to the lateral edge of the accessory olive ; it is not marked 

 immediately above the pyramidal decussation. 



