596 ^Journal of Comparative Neurology and Psychology. 



stehen, ist f reilicK nicht von Feme zu errathen • doch darf man 

 vielleicht an den Tensor veli palatini und den Tensor tjmpani denken, 

 schwerlich an den ]\Ijlo-liyoidens nnd Biventer anterior."' It must 

 be said that Kolliker's figures are not convincing as to the statement 

 that the bimdle in question joins the motor root. 



Van Gehuchten (1895) studied the origin of this root in Golgi 

 silver preparations of the young trout. He describes and figures two 

 cells with their fibers. One cell is bipolar. It has an ascending 

 slender branching process which Van Gehuchten calls a dendrite and 

 a very coarse sinuous descending process which he calls the axone. 

 The descending process passes out in the sensory root of the trigemi- 

 nus. The other cell is unipolar, but its large process divides at a 

 short distance from the cell. One branch is a coarse descending- 

 process which runs to the level of the trigeminal root. The other 

 branch consists of several slender processes which Van Gehuchten 

 calls dendrites. Van Gehuchten decides that the descending root is 

 motor in function and says : ''Le f aisceau de fibres nerveuses appele 

 par les auteurs racine superieure du nerf trijumeau, appartient done 

 en realite, au moins chez la truite, au nerf de la cinquieme paire. 

 Cette racine superieure constitue une racine motrice. Cette con- 

 clusion importante est en pleine concordance avec les previsions de 

 Kolliker. Le savant anatomiste de Wurzbourg s'est prononce en 

 faveur de la nature motrice de la racine superieure, en se basant 

 uniquement, comme il le dit lui-meme, sur ^die Dicke ihrer Fasern, 

 der Anschluss an die Portio minor, die Grosse ihrer Ursprungszellen 

 und die Unmoglichkeit einer anderen Deutung.' 



"N^otre conclusion, au contraire, est basee sur un fait positif; 

 nous avons vu le prolongement cylindraxile d'une de ces cellules 

 nerveuses se recourber en dehors et devenir fibre constitutive du nerf 

 peripherique." 



Cajal (1896) was so fortunate as to have these cells and fibers 

 beautifully impregnated by the Golgi method in the mouse, and the 

 prevailing notions regarding this root rest chiefly, perhaps, on his 

 description. The essential points are clearly illustrated in his Figs. 

 1 and 2. The cells are unipolar in the adult form, although in em- 

 bryos they may have several small dendrites. The thick process is 



