346 



either rolling to the affected or to the normal side, it seems not very 

 risky, to admit 2 connections from this canal to separate cellgroups 

 in DEiTRRS-complex. As Marchi-preparations do not allow a further 

 analysis of the nuclei, we can only suppose, that the Ramus des- 

 cendens Nnc. Vestibularis controls the rolling to the normal side, the 

 more proximal part of DEiTERS-complex the rolling to the affected side. 



Equally for the circus-movement a similar arrangement can be 

 recognised. An important difference is only this detail, that one of 

 the two ascending connections of the cellgroup, that controls the 

 circus-movement to the affected side, crosses the raphe. 



The whole of the posterior longitudinal bundle together with its 

 lateral wings (F. D. A.), we find thus composed by 2 descending 

 and four ascending systems of fibres. The two innermost bundles are 

 descending ones from the nuclei of the posterior commissure, the 

 medial one degenerating to the medulla, the lateral one to far down 

 the spinal cord. The first one (connnissuro-medullary bundle) is found 

 degenerated after the lesions in the region of the posterior commis- 

 sure, that had caused circus-movement to the affected side. The second 

 bundle (f. interstitio-spinalis) has probably nothing to do with the 

 forced movements. 



The middle part of the entii'e P. L. B. system is composed of 

 two ascending bundles, originating in Deiter's complex. The inner- 

 most, more voluminous one, contains crossed fibres, F. vestibulor 

 mesencephalicus cruciatus, the lateral one homolateral fibres (F. Ves- 

 tibulo-mesencephalicus homolateral is). 



After section (and ascending degeneration) by a lesion of the 

 Deiters' complex of either of these bundles circus-movements to 

 the normal side are performed. 



The outmost part of the P. L. B. -system is composed of two 

 ascendent bundles either of them originating in the Detters' com- 

 plex and terminating in the teginentum little beyond the level of 

 the trochlear nucleus. The outmost of these two bundles (probably 

 from the proxinuxl parts of Deiters' complex) elicits by its ascending 

 degeneration roUing movements to the ■ affected side (F. vestibulo- 

 tegmentalis lateralis), that of the innermost one (probably arising 

 from the Ramus descendens) rolling movements to the normal side 

 (F. vestibulo-tegmentalis medialis). 



As far as I can judge, the relative situation of these bundles is 

 pretty constant, but the ascending fibres intermingle more than the 

 descending ones. Jsot rarely the bulky crossed vestibulo mesen- 

 cephalic bundle holds in the cross-section an area far beyond the 

 P. L. B. proper. 



