OF THE NERVUS OCTAVUS. 87 



has proved , that they disappear totally after a partial section of 

 the crossed lateral fillet. 



For all these arguments it may be accepted as a certain fact , 

 that from the large pyramidal cells in the tuberculuin acusticum 

 originates a secundary system. Why then, those cells do they not 

 suffer any atrophy after root-section made long before ? It appears 

 to me , that the cause of this behaviour after rootsection may be 

 found in the circumstance , that the collaterals of the rootfibres do 

 not terminate directly at the large pyramidal cells. I believe that 

 the small elliptical-cells in the deeper layers, the cells accumulated 

 along the root-fibres, the cells of the proper nucleus of the dorsal root, 

 are cells intercalated between the rootfibres and the secundary system. 



And as for the ventral nucleus, it seems to me that the same 

 view may be defended. 



This nucleus is reduced very much in cases of atrophy , to 2 / 5 of 

 its original size as compared with that of the other side. Its ventro- 

 distal end has suffered the greatest changes. The loss of fibres in 

 this nucleus is enormous, and according to it the cells are lying 

 close together. I cannot completely agree with ONUFROWICZ that 

 the cells disappear in the nucleus, or that they are found to have 

 diminished in size so very much as his drawings represents it. 



This only is the case in its disto-ventral pole, where again the 

 small elliptical cells are found. In the dorso-capital regions there are 

 found a great many cells, which have degenerated not at all or very 

 slightly, but they are lying closer together, because the bundles of 

 root-fibres are gone. Here in this nucleus I believe that again the root- 

 fibres do not immediately terminate at the larger cells, from which 

 secundary systems originate, but by means of intercalated small cells. 



And such may be also the case in the olivary bodies, where 

 again small cells may disappear, but the larger ones are found 

 unaltered. Only this is not the case in the cells of middle size 

 from the nucleus corporis trapezoides. Here as MAiicui-preparations 

 show, the degenerated collaterals of the rootfibres fill up the nucleus. 

 Moreover the peculiar terminations at the cells (the ,,Endfusschen" 

 of HELD) in this nucleus is kwown. But in this nucleus 4 - opposite 

 to the rootsection the cells are not only lying closer one to 



another than in the nucleus, corresponding to the undamaged root, 

 but they are considerably reduced in size. 



I believe that the dorsal root entering at the distal end of the nucleus 

 ventralis, provides this nucleus with rootfibres, and afterwards entering 

 in the deep medullar layer also provides the tubercnlum acusticum , 

 and that the ventral root only enters in these nuclei with a few dorsal 



