OF THE NEKVUS OCTAYUS. 163 



But it is not the sole octavo-motor system. 



From DEITERS cells, from the large cells of the tuberculum 

 acusticum and from the ventral nucleus new secundary systems issue. 

 They all cross the raphe, be it either as transverse dorsal fibres, 

 or as MONAKOW'S fibres, or as HELD'S intermediary fibres. 



Before doing so, however, they send ascending fibres in the 

 fasciculus longitudinalis posterior providing the nucleus of the N. 

 abducens and the proximal motor eye-nuclei. They send also des- 

 cending fibres to the nucleus of the XII th nerve , and through the 

 fasciculus praedorsalis, the anterior column and the anterior commissure 

 towards the cervical part of the motor horn of the spinal cord, 

 and though much reduced in number even to the thoracic and 

 lumbo-sacral part of it. Moreover transverse dorsal fibres inner- 

 vate the contra-lateral nucleus of the n. abducens to a considerable 

 degree. 



In this way new homolateral tracts, though they have a slight 

 representation in the homonyme tracts of the opposite side, originate. 

 They chiefly are composed of secundary fibres accompanied by a 

 few rootfibres, in the beginning of their course. They may be 

 considered as another homolateral octavo-motor system , not quite 

 so important as the tract of DEITERS but still considerable enough 

 to be mentioned. 



There are however still other octavo-motor systems, perhaps of 

 greater complexity. 



We have seen a small quantity of rootfibres and of secundary 

 fibres reach the homolateral ventral spinal cerebellar ascending tract 

 (GowEii's antero-lateral tract) and seeking on this way, in the path 

 followed by ascending spinal fibres , the homolateral as well as the 

 hetero-lateral medial nuclei tecti. Moreover some rootfibres pene- 

 trating through BECHTEREW'S nucleus directly enter into those nuclei. 



Now , as VAN GEHUCHTEN , controlling researches of RUSSELL , 

 THOMAS , PROBST has proved x ) , from the medial nuclei tecti , a tract 



*) I can completely affirm VAN GEUUCHTEN'S statement, that after the medial trans- 

 verse section of the cerebellum on hoth sides a tract degenerates, at first ascending along 

 its internal border, then bending round the pedunculus superior, redescending lateraly 

 from it, between the spino-cerebellar ascending ventral tract and bracchium conjunctivum 

 pedunculi superioris to seek its place between area ovalis C. R. and the spinal root of 

 the fifth nerve. It sends endings, methinks , among the nucleus BECHTEREW , DEITERS and 

 nucleus griseus r. descendentis , and a few fibres (VAN GEHUCHTEN'S bifurcation) may 

 find their way in the descending tract of DEITERS; whereas other fibres still descend 

 towards the nucleus of BURDACH. 



I believe the here described tract to be a constituent of the congenial system of 

 kinaesthetic nature, rather than of octavo-motor nature, and I therefore mean the 

 experiments upon this bundle to be beyound the limits of these researches. 



11* 



