162 C. WINKLER. THE CENTRAL COURSE 



octavus-nucleus) along the medial trunk (in the nucleus proprins of 

 the medial trunk) along its continuations , the descending and ascen- 

 ding roots (in the nucleus griseus rami descendentis , in the nucleus 

 BECHTEREW, in the dorsal nucleus of the n. octavus) and along 

 the beginning of the ventral trunk (in the olivary bodies). 



These cells may be regarded as intercalated cells, making con- 

 nection between primary rootfibres and greater cells from which 

 secundary systems originate, helped sometimes for this purpose by 

 direct collaterals of rootfibres. 



For instance both nuclei of the N. abducentes are certainly inner- 

 vated by direct collaterals of rootfibres of the descending root, the 

 hornolateral facial nucleus receives directly rootfibres of HELD'S 

 intermediary system. A few rootfibres innervate directly the proxi- 

 mal motor nuclei of the eye, by means of ascending rootfibres in 

 the fasciculus longitudinalis posterior. 



The larger cells in the tuberculum acusticum and in the dorso- 

 proximal portion of the ventral nucleus, not disappearing after root- 

 atrophy and in that case undergoing only slight atrophical changes 

 after rootatrophy, receive root-collaterals but mostly are connected 

 to the root-fibres by means of intercalate cells. 



The gigantic cells in the nucleus of DEITERS, not or nearly not 

 altering after root-atrophy, do not receive any direct collaterals of 

 the roots. Their connections with rootfibres are only made by means 

 of numerous cells found in the corpus juxtarestiforme (nucleus 

 griseus rami descendentis, nucleus BECHTEREW) and in the dorsal 

 octavus-nucleus, surrounding the nucleus of DEITERS on all sides. 



These cells are forming links between rootfibres and the very 

 important octavo-motor secundary systems, issued from the cells 

 of DEITERS. 



They are two important tracts. The one, the ascending DEITERS tract, 

 connects those cells to the nucleus of the trochlear nerve and the 

 distal part of the oculomotor nerve. The other, the descending 

 DEITERS tract, connects them, to the nuclei of the VI th , VII th , 

 X th , XI th , nerves, to the nuclei in the formatio reticularis late- 

 ralis of the oblongata and through the lateral column with the 

 motor horn of the cervical cord. It may even be pursued, though 

 much reduced, towards the sacral portion of the cord (page 119 125). 



These secundary systems are chiefly hoinolateral tracts. A. few of 

 their fibres only enter in the homonymous contralateral tracts. They 

 are accompanied by a few primary rootfibres. 



In this way the first and most important octavo-motor system 

 is constituted. 



