23O NERVOUS SYSTEM. [SECT. 115. 



fibres connect the ganglia, on the one hand, with the cerebellum 

 and medulla oblongata, and, on the other, with the hemispheres of 

 the cerebrum. 



The corpus striatum contains two large grey nuclei, the nucleus 

 caudatus, situate anteriorly and superiorly, and the nucleus lenticu- 

 laris, inferiorly and posteriorly, which, however, are connected an- 

 teriorly with each other, and form one mass; also the thin nucleus 

 tceniceformis with the amygdala, to the outer side of the lenticular 

 nucleus. The corpus striatum is principally connected with the 

 base of the cerebral penduncle or the contination of the pyramid, 

 which spreads out in it with numerous white fibres. The grey 

 substance, as is almost everywhere the case, exhibits nerve-cells 

 and fine nerve-fibres. The former, of o'oob'" to o*oi8'" in size, are, 

 in part, colourless ; in part, as especially in the nucleus caudatus 

 and third section of the nucleus lenticularis, pigrnentated ; they 

 have two to five processes, and their number is proportionate to 

 the depth of colour of the grey substance. 



The nerve-fibres can, for the most part, be referred to the base 

 of the cerebral peduncle. They are dark-bordered tubes, of 

 o*ooi2'" to o , oo5' // , mostly of 0-002'" to o - 004'" in size, which 

 lying parallel to each other, penetrate in a straight direction into 

 the first division of the lenticular nucleus, and the most anterior, 

 thickest part of the caudate nucleus. If they be followed further in 

 the lenticular nucleus, they are seen to form larger and smaller 

 bundles, and then, decreasing somewhat in thickness (the most of 

 them measure 000 12'" to 0003'"), to pass in a straight direction 

 through the less abundant grey substance of the two" first divisions 

 of it, in order, at last, to radiate in form of pencils into the outer- 

 most largest division, where they are lost to view. That is to say, 

 white bundles of coz)/" to o - i4'", with fibres from o - ooi2'" to 0*002'", 

 pass parallel to one another from the second division into the 

 third, which bundles, slightly diverging and dividing into smaller 

 ones, proceed further towards the outer border of the lenticular 

 nucleus, and before they have reached it, disappear to the naked 

 eye. If these fibres be followed microscopically in chromic acid 

 preparations, it is found that the bundles proceed to near the 

 outermost part of the lenticular nucleus, gradually, however, sepa- 

 rate into smaller bundles and separate fibres, and become inter- 

 woven with one another in various ways. That these fibres terminate 

 here, and do not proceed farther into the white substance of the 

 hemispheres, may be regarded as established, since not a trace 

 of their further progress is observable; and were they really 



