258 Journal of Comparative Neurology. 



which pushes the nucleus towards the periphery of the cell-body 

 and even beyond the normal outline so that it projects. At the 

 same time the outline of the nucleus loses the round shape. 

 The dendrites are somewhat less involved, but also a little dif- 

 fusely stained. A good illustration of this condition is furnished 

 in a paper on facial paralysis by Dr. Adolf Meyer, in the Jour- 

 nal of Experimental Medicine, Vol. II, No. 6. 



There remains to be said that the cell recuperates as the 

 regeneration of the fiber takes place and that the cell atrophies 

 if no regeneration can take place or especially where the fiber 

 is torn or cut off close to the point of exit from the neural-tube. 

 (This explains the bad prognosis of 'radicular ' paralysis.) 



In this manner we have not only established the physio- 

 logical connection between the cells of the hypoglossal nucleus 

 and the hypoglossal nerve but some important laws concerning 

 the neurones. The Golgi stain gives evidence in a few of the 

 cells that the axone extends into the hypoglossal root. The 

 above method shows that all the cells react in the same way to 

 injury of the nerve and the conclusion is safe that all the cells 

 which show this change are hypoglossal neurones. That the 

 peripheral stump of fibers of a cut hypoglossal nerve degener- 

 ate has been shown by Waller and many investigators after 

 him; that the same injury affects the cell-body as well, is dem- 

 onstrated by Nissl; Bregman has also shown that tearing out of 

 a facial nerve in an adult guinea-pig is followed by a partial 

 degeneration of the central stump of fibers (demonstrated by 

 Marchi's method), in which case the degeneration of the fibers 

 goes hand in hand with deterioration of the cells. And in the 

 new-born this ' atrophy' and degeneration are complete, ending 

 in resorption (v. Gudden, Forel). 



All these data are in perfect harmony with the conse- 

 quences of the neurone-theory. The cell-body is the vital focus 

 of the neurone. Not only do the processes die when cut off 

 from it, but the cell-body is influenced by an injury to the neu- 

 rite and if the greatest part of the neuritc is cut off, the cell is 

 subject to atrophy and perhaps even to complete rcsorj)tion. 

 The fact that the reaction is limited to the neurone and does 



