440 THE INTERNAL STRUCTURE 



within by the radiating fibres of the Crus ('internal 

 capsule ') ; and externally (fig. 157, C x) by a thin stratum 

 of fibres (' external capsule ') issuing from its interior for 

 distribution to various regions of the Hemisphere, though 

 forming in the first part of their course to the convolu- 

 tions (together with some other fibres from the ' fasiculus 

 uncinatus ' to be hereafter described) an outer wall, 

 serving to separate this inferior portion of the Corpus 

 Striatum from the immediately adjacent convolutions of 

 the * island of Reil ' the situation of which has been 

 already defined (see pp. 301, 341, 381). 



b. Relations of fibres composing the Cerebral Peduncles 

 as well as of fibres issuing from or going to the Central 

 Ganglia, with different Convolutions of the Cerebral Hemi- 

 spheres. It is easily to be demonstrated, according to 

 Broadbent, that " fibres of the crus in large numbers pass 

 uninterruptedly through or by the Central Ganglia to the 

 Convolutions." And he adds, "In the case of the fibres 

 of the posterior edge of the Crus there is scarcely room 

 for error on this point, as they do not come at all into 

 relation with grey matter on their way."* 



Other fibres of both ' tegment' and ' crust,' seem to end 

 in or take their origin from the grey matter of the Corpus 

 Striatum, though Broadbent is inclined to believe that 

 " no fibres of either division end in the Thalamus."t 



From both Thalamus and Corpus Striatum, however, 

 many independent fibres appear to issue, which serve to 

 connect these ganglia with Convolutions in different parts 



* Some of these fibres which merely pass through or by the 

 Central Ganglia may, as certain anatomists suppose, serve to con- 

 nect the Cerebral Cortex with the Cerebellum, by way of its 

 ' middle peduncles.' 



f This seems a very doubtful proposition. The anatomical rela- 

 tions of the Thalami are, however, as yet, as uncertain as are their 

 functions. 



