THE BRAIN AND ITS MEMBRANES. 717 



upward into the pons, of which they should be considered a part, and then pass 

 into the cms cerebri (mid-brain) and internal capsule (hemisphere) of the same 

 side (Fig. 422). 



The olivary body, due to the projection of its dentate nucleus (see above), has 

 on its surface (or is made up of) longitudinal fibres continued up from the lateral 

 tract immediately beneath it. The fibres of this lateral tract have already been 

 traced upward from the cord. Some now pass upward over the surface of the 

 olive to its upper end, where they dip into the deep portion of the medulla and 

 join the fibres from the lateral tract, which have already passed beneath the olive 



Superficial 

 fibres of pons 

 reflected. 



FIG. 422. Superficial dissection of the medulla oblongata and pons. (Ellis.) 



(see " lateral surface " of medulla for this and paragraphs immediately preceding 

 and following). 



Fibres in the Grooves. Those in the dorse-lateral groove are the continuations 

 upward of the antero-latcral ascending cerebellar tract (column of Gowers) of the 

 cord. At the upper end of the groove they dip into the formatio reticularis, and 

 pass at once into the dorsal part of the pons. Here they reach the corresponding 

 superior peduncle of the cerebellum, turn backward and mesially in this, and 

 then pass into the superior medullary velum, and are thus continued into the 

 white matter of the worm or middle lobe of the cerebellum. 



Those in the vcntro-lateral groove on reaching its upper end maybe considered 

 to dip into the formatio reticularis, and then bend dorsally over the top of the 

 olive to join the fibres of the restiform body, and thus reach the cerebellum. 

 They are the upward prolongations of the antero-lateral descending cerebellar 

 tract (column of Loewenthal) of the cord. 



The Restiform Body. As before . stated, each of these columns is the largest 

 tract on its own half of the medulla, and receives the fibres of the direct cerebellar 

 tract (dorso-lateral ascending cerebellar tract Flechsig's column), the antero- 

 lateral descending cerebellar tract of the cord, and the external arciform fibres. 

 It receives also other bands of fibres from the formatio reticularls of the medulla, 



