OF THE NERVUS OCTAVUS. 183 



tract should have been directly damaged by the incision. 

 Notwithstanding the rubro-spinal tract is degenerated in 

 a rather important manner. 



PLATE XXL 



Fig. 3. A frontal section through the oblongata of a rabbit 16 

 days, after the transverse division of the lateral trunk 

 of the corpus trapezoides (by x), at the entrance of the 

 octav us-roots, in order to demonstrate the degeneration 

 in the corpus trapezoides. 



PLATES XIX, XX at XXI. 



Fig. 25 A o. A series of frontal sections through the central 

 system of a rabbit, eight days, after a double-sided 

 ablation of the tuberculum acusticum. In fig. 25 E i 

 (by x) the double-sided injury is surrounded by a sharp 

 line to make it demonstrable. 



PLATE XIX. 

 Fig. 25 A. The most proximal section through the corpora quadrigemina anteriora. 



There is an intense degeneration on both sides in the ventral layer 

 of fibres of the nucleus corp. quadr. postici. 



Moreover an intensive degeneration (more on the left than on the 

 right side) in the fasc. long. post. , here united with the ascending DEITERS 

 tract, and in both nuclei of the IV th nerve. 



Fig. 25 B. The section through the corpora quadrigemina posteriora and the lateral 

 fillet. 



There is an intense degeneration in the lateral fillet, especially in its 

 medial bundle (f. in. 1. 1.), and in its lateral layer the fibres round the 

 ventral nucleus have degenerated. 



The fasc. long. post, begins its separation from the tract. DEITERS 

 ascend. (The separation between the two tracts is distinct In fig. 25 c 

 D and E) and fibres detach from the ascending DEITERS tract during its 

 course to reach the medial bundle of the fillet. In the decussatio ven- 

 tralis tegrnenti another degeneration is found , reaching the place where 

 the //aberrirendes Seitenstrangbiindel" enters into the lateral fillet. The 

 most lateral fibres of the fillet remain without degeneration. 



Fig. 25 c. The section touches the place, where the pedunculi cerebelli medialis 

 leave the medulla. 



Degenerate fibres are found in 1'y The fasciculus longitudinalis posterior, 

 2'y the ascending DEITERS tract (which at this moment leaves the f. 1. p. 

 to deviate laterally). Eoth tracts send transverse fibres crossing the raphe , 

 that may be followed in 3'y the medial bundle of the lateral fillet. 



4'y. The lateral bundle of the fillet with the nucleus ventralis lemnisci. 

 5'y transverse fibres in 'the ventral decussatio tegmenti towards the place 

 of the //aberrirendes Seitenstrangbiindel" 6'y the fasciculus spino-cerebel- 

 laris ascendens ventralis. 



Fig. 25 D. The section touches the middle of the nucleus ventralis lemnisci. There 

 are found the same degenerations as in the former. The ventral decussatio 

 tegmenti has ended, its degenerated area finds a place laterally from the 

 nucleus ventralis lemnisci. 



