Anatomy of the Brain. 559 



each other as that between the front and posterior sides of the spinal 

 cord. The corpus striaturn is a reddish gray mass of flabby consistence 

 more friable, and easily lacerated by congestions, than the optic thalamus, 

 a fact which explains why it is that paratysis of motor power results 

 from disease oftener than paralysis of sensation. The ends of the motor 

 or anterior and lateral fibres of the crura cerebri, penetrate the corpus 

 striatum in all directions in the shape of serpentine filaments. These 

 antero-lateral bundles of nerve fibres are finally terminated in the yeliow 

 nucleus which lies in the central and lower or anterior part of the corpus 

 striatum and is in part within the lateral ventricle, and in part is pressed 

 out under the edge of the overhanging cerebral hemisphere. This yellow 

 nucleus is of firmer consistence than the rest and is peculiar!}^ striated. 

 A large part of the lateral fibres which terminate in the yellow nucleus 

 are connected backwards with the pednucles of the cerebellum, and ac- 

 cording to Luys are afferent to the corpus striatum, bringing to it the 

 condensed co-ordinated stimuli of the cerebellum. The gray matter of 

 corpus striatum is composed of an infinite number of large polygonal 

 cells with many prolongations in various directions, their size being 

 similar to that of the large cells in the cortex of the cerebrum, to be 

 described. They have the same general character as all other cells, 

 having the nucleus and nucleolus and the branching prolongations which 

 rapidly taper away and mix with the similar prolongations of their 

 neighbors, the result being a dense mass of delicate network. There are 

 also great numbers of small cells, especially in the yellow nucleus. 

 They have a large nucleus of yellowish color, and they resemble the 

 small cells which are scattered among the large ones in the cerebral 

 cortex, and they are also in substance like the small cells in the cerebel- 

 lum. They are possessed of a very fine fringe of little roots which are 

 lost in the network formed by the larger cells. In addition to these 

 components are the capillaries of the blood vessels which penetrate 

 among the nerve fibres from below upward. The efferent fibres from 

 the corpus striatum originate in the plexuses of cells in the gray mass 

 of the body where they are indistinguishably mixed up with the afferent 

 fibres from the crura cerebri cerebellum and optic thalamus. From 

 there they pass downward in bundles isolated from each other, which are 

 collected into masses and form the anterior columns of the crura cerebri 

 or peduncles of the brain. These are the motor fibres, the afferent fibres 

 from the cerebellum being connected with the posterior columns of the 

 crura cerebri. The motor isolated bundles are distributed to the differ- 

 ent ganglions of the motor nerves which connect with the medulla ob- 

 longata and spinal cord, dropping out from the general mass of the 

 spinal axis one at a time, as the root connections of the several nerve 

 trunks are reached. Only the posterior end of the corpus striatum is 



