OF THE NERVUS OCTAVUS. 165 



show the peculiar position of neck and head towards the operated 

 side under the influence of the remaining contra-lateral impulses 

 and are atonic at the homo-lateral, especially at the fore-leg. 



The anatomy of the octavus-nerve may be fit to explain (p. 27) 

 the facts, that physiologists have taught us to be consequent to its 

 loss on one side, as regards the motor functions of the nerve. 



Atony in all the homolateral muscles of head, neck and shoulder, 

 together with an incomplete relaxation of eye-muscles, differing on 

 both sides, may be sufficient to explain the forced position of head , 

 neck and eyes towards the lost impulses. The correction of these 

 forced attitudes, following immediately on the removal of the second 

 labyrinth, their being replaced by a general atony in all muscles, 

 is in perfect accordance with the here adopted anatomical views (p. 37). 



All disorders of motility however are produced without any inter- 

 ference of a conscious sensation of equilibrium. 



Anatomically spoken, they are produced in subcortical systems. 



Physiologically spoken, they are automatic motions. 



Moreover the anatomy teaches us, that rootfibres of both roots 

 may contribute to the different octavo-motor subcortical systems. 



Another important octavus-system however exists, the details of 

 which are described in the second chapter, equally composed of 

 different fibres and centra. 



The greater part of all fibres composing it crosses the raphe before 

 taking an ascending course. 



From those the most interesting are MONAKOW'S fibres. Issued 

 from the dorsal system, and without any doubt being axons from 

 the large cells in the tuberculum acusticum, they reach, through 

 the dorsal layer of the crossed oliva superior, the medial bundle 

 of the internal and lateral fillet. Before crossing the raphe they 

 send descending fibres (collaterals) in the fasciculus praedorsalis of 

 the octavo-motor system. 



In the lateral fillet they meet with fibres of different origin, but 

 taking all a part of their way in the ventral or in the intermedi- 

 ary octavus-system. 



A few of them are rootfibres, more are originating in the crossed ven- 

 tral octavus-nucleus, still more in the crossed oliva superior and nucleus 

 para-olivaris. A great many of them issue from the homolateral nucleus 

 trapezoides and from the homolateral nucleus ventralis lemnisci. 



All together they participate to the very complicated tract, which 

 is called the lateral fillet. The greatest number of them is medul- 

 lated at birth (root-fibres, HELD'S fibres, the layers a and b in the 

 corpus trapezoides, and a part of MONAKOW'S fibres), others have 



