THE MEDULLA OBLONG AT A AND TEGMENTUM OF THE PONS. 197 



must bo distinct from the former, because it becomes medullary 

 at a much later period. These are the fibres from the opposite 

 olivary bodies. Inasmuch as they come from the cerebellum 

 and can be traced no farther downward than the olivary bodies, 

 let us give them the name of cerebello-olivary fibres of the resti- 

 form body. It is only after the addition of these fibres that the 

 posterior cerebellar peduncle becomes a larger structure than 

 that shown in Fig. 110, when it consisted only of the fibres 

 from the spinal cord. 



The olivary body, a medullary 

 structure whose wavy outline you 

 have seen on many of the previous 

 figures, consists of a mass of neu- 

 roglia, in which are imbedded in- 

 numerable small ganglion-cells. 

 What the relation is between these 

 cells and the nerve-fibres which run 

 to the olivary bodies is, it is impos- 

 sible to state. 



Large masses of fibres emerge 

 from the restiform body, and sur- 

 round the olivary process externally 

 in front and behind. They pass 

 through its medullary lamina, and in 

 the interior are gathered into a thick 

 bundle of nerve-fibres, which emerges from the hilus of the 

 olivary body, crosses the raphe, and can be traced into the olivary 

 body of the opposite side. If one-half of the cerebellum is 

 destroyed, the opposite olivary body degenerates. Dorsad of the 

 olivary body, in the vicinity of the substantia reticularis, a num- 

 ber of fasciculi pass upward in the tegmentum, in company with 

 fibres Avhich are given off from the net-work surrounding the 

 ganglion (Bechterew's central tegmental tract, Stilling's remnant 

 of the lateral column). 



The cerebello-olivary tract of the restiform body has its 



Origin of the spinal-cord portion of 

 the restiform body. Most or all of the 

 fibres end in the vermis. 



JHnlfr-Stranijr, Post, columns. 

 Kleiuh. S. 13., Lateral cerebellar tract. 



