522 THE BRAIN OF MAMMALS, BY TH. MEYNERT. 



and connect each of them with another similar half, so as again 

 to form one whole, the distended base, directed towards the 

 granules of the commonly called "flask-shaped" body with 

 its (probably) single process, would by its duplication repre- 

 sent one of those vesicular forms, poor in processes, that are 

 connected with the sensory roots in the interspinal ganglia, 

 in the Gasserian ganglia, and in the descending roots of the 

 fifth (see p. 448). The half which passes into the neck of the 

 flask, that is to say, by gradual attenuation into the thick 

 processes turned towards the pure grey layer, would, on the 

 other hand, by its duplication, represent one of the slender 

 forms, rich in thick processes, that form the nuclei of origin 

 of all motor roots. 



The nerve cells of Purkinje would consequently (if the 

 statements of Deiters, Koschewnikow, and Hadlich, in regard 

 to their unbranched connection with one axis-cylinder be cor- 

 rect) be connected by that extremity which is formed on the 

 type of a sensory cell, with one centripetally conducting fibre, 

 and through its branched extremity, constructed on the type 

 of a motor cell, with several centrifugally conducting fibres. 

 The circumstance that the smaller (poorer in fibres) restiform 

 body passes into the posterior column of the spinal cord, 

 whilst the far larger (more abundantly fibrous) processus ad 

 p on tern is connected with the crusta, which, on account of its 

 origin from the lenticular and caudate nuclei, is motor, de- 

 monstrates that in general the proportionate size of these 

 cerebellar arms corresponds with the relative numbers of 

 these two forms of cell processes, and supports the view 

 that in each of the cells of Purkinje we have a nodal point 

 which effects the looping of two tracts having different sig- 

 nificance. 



6. THE STRUCTURE OF THE TRANSITIONAL REGION BETWEEN 

 THE MEDULLA AND SPINAL CORD. 



In the formation of the anterior and posterior divisions of 

 the medulla oblongata, the double nature of the cerebral pe- 

 duncle, which had been foreshadowed by the separation of 

 the chief groups of cerebral ganglia, and had become fairly 



