128 



LECTURES ON THE CENTRAL NERVOUS SYSTEM. 



whole inner and the whole outer third of the pes go no farther 

 than the pons. Below this point only the fibres of the middle 

 third, the pyramidal tract, appear. The accompanying figure 

 shows this and gives a front view of the pons, together with the 

 crura cerebri and the cerebellum. The pyramidal tract is 

 shaded dark. 



Fig. 74 shows in diagram the arrangement and course of 

 fibres in a section through the pons. The fasciculi come from 

 above on each side, out of the cerebellum, surround and pene- 



FIG. 73. 



The pedunculus cerebri and the pons seen from in front. That tract of the crusta which 

 does not terminate in the pons is shaded dark. 



Hirnachen&el, Peduncnlus cerebri. 



Kleinhirn, Cerebellum. 



Pyramide, Pyramid. 



trate the fibres of the pes, and, crossing over to the opposite side, 

 are associated with the longitudinal bundles of the latter. It is 

 pretty well established that they are connected with a good 

 share of the fibres of the pes and serve to establish a communi- 

 cation between them and the cerebellum. How this is effected 

 is not known. Numerous ganglion-cells lie among the fibres 

 of the pons. These are caught in a fine net-work of medullary 

 fibres, and to this net-work only can the fibres of the pes be 

 traced on the one hand, and the fibres of the pons on the other. 

 This much is certain, that bundles arise from the region of 



