564 THE CEREBRUM. 



ventricle ; the other, or extraventriciihir, situated more externally and 

 inferiorl)^, is hidden in the white mass of the hemisphere. It is sepa- 

 rated from the first by the white substance of the corona radiata, which 

 appears on a horizontal section as a broad white band extending from 

 behind forward between the two grey masses, and traversed by streaks 

 of grey matter passing from one to the other. The intraventricular part, 

 also named the nucleus caudatus (corpus striatum proper of Henle and 

 others) is connected below with the lamina cinerea, and with that part 

 of the grey matter of the optic thalamus v.diich is seen in the third 

 ventricle. The extraventricular part, named nucleus lenticularis, is 

 continuous below with the caudate nucleus, and with the grey matter 

 of the anterior perforated space. Stria? of grey matter pass from one 

 centre to the other. Between the lenticular nucleus and the island of 

 Eeil, which lies opposite to it, there intervenes a thin lamelliform 

 deposit of grey matter, the claustrum (Burdach), nucleus tmiiceformis 

 (Arnold), which, in transverse section, is seen as a thin line. 



The caudate nucleus presents nerve-cells, large and small, in great abun- 

 dance, scattered among the fibres which pass through it, and embedded 

 in a granular substance containing nuclei. Three forms of cells have 

 been described, — large multipolar cells, about T2V0 ^^^ch in diameter, 

 having branching processes, and containing rounded nuclei and pig- 

 ment ; similar but smaller cells, about half that size, and small 

 elements like nuclei, but differing from the nuclei of the connective 

 tissue. No axis-cylinder process has been distinguished in any of the 

 cells of the corpus striatum. Peculiar clear spherical areas, containing 

 a large granule, a nucleus, or a nucleus surrounded by granules, also 

 occur in it (Henle). 



Of the lenticular nucleus the two inner zoneig (see p. 549) contain 

 numerous large branching nerve-cells, yellowish in tint, many of them 

 surrounded by clear spherical areas. The striation of tiie outer zone 

 is due to radiating bundles of nerve-fibres alternating with grey matter 

 in which are clear spaces containing gi'.anules and nuclei, such as are 

 found in the corpus striatum. 



The claustrvm contains sc?attered nerve-cells, most of which contain 

 yellow pigment, and which resemble in their fusiform shape and bipolar 

 processes the cells of the posterior vesicular columns of the spinal cord. 



Meynert's TerminologT- — According to Professor Meynert, of Vienna, tlie 

 structural arrangement of the brain differs in many respects from tlie descrip- 

 tion commonly given of it. His terminology also differs fi-om that in ordinary 

 use. The details of the conclusions to which he arrives will be found in his article 

 on the brain, in Strieker's '• Handbook of Histology." 



He groups the gi'ey substance of the central ner-\-ous system into foiu* 

 categories. 



1. The superficial grey substance of the cerebral hemispheres. 



2. The grey substance of the cerebral ganglia (corpus striatum proper, lenti- 

 cular nucleus, optic thalamus, corpora quadrigemina, locus niger, &c.). 



3. The grey substance Avhich surrounds the central cavities of the brain and 

 spinal cord. Commencing above at the infundibulum. it lilies the fifth ventricle 

 and the aqueduct of Sylvius, extends through the foui-th ventricle, and surrounds 

 the canal of the spinal cord. 



4. The cerebellum and its appendages, including the gre}- substance traversed 

 by its commissural fibres in the anterior medullary velum and the pons. 



If the whole tract of nervous conduction, from the g'rey matter of the cerebral 

 convolutions, on the one hand, to the peripheral temrinations of the nerves of 



