620 



THE BRAIN. 



ventral section, taken still more anteriorly through the frontal lobe (Fig. 

 141), the head of the nucleus caudatus is seen at about it greatest size, and 

 the diminishing nucleus lenticularis (NE), represented by the putamen alone, 

 is becoming fused with it, the two nuclei being separated by a small quantity 

 of white matter of the internal capsule, and that largely broken up by 

 bundles of gray matter, giving rise to a striated appearance. In a similar 

 section still further forward, the nucleus lenticularis would be absent, the 

 head of the nucleus caudatus appearing by itself. Returning to the hinder 

 part of the hemisphere, we find in a dorso-ventral section taken through the 

 hind limb of the capsule (Fig. 139) that while the nucleus lenticularis is 



FIG. 141. 



Diagrammatic Outline of a Transverse Dorso-ventral Section of Right Hemisphere (Man) 

 through the Frontal Lobe. (Sherrington.) Natural size. Nc, head of nucleus caudatus, and Nl, 

 the front end of the putamen of the nucleus lenticularis becoming fused with it ; cc, corpus cal- 

 losum, cut through at its front bend or rostrum, so that both dorsal and ventral portions are 

 shown ; between these is seen the fifth ventricle or cavity in the septum lucidum SI; Iv, lateral 

 ventricle ; Cl, claustrum ; F, frontal lobe. Cortical gray matter, as in Fig. 140, left unshaded. 



here at its greatest size, the head of the nucleus caudatus (Nc), lying dorsal 

 to the nucleus lenticularis and separated from it by a considerable thickness 

 of internal capsule, has much diminished ; the same section, moreover, 

 shows ventral to the nucleus lenticularis and clinging to the descending 

 horn of the lateral ventricle (Lv.d.~), the extreme tip of the tail of the nucleus 

 caudatus (Nc) soon about to fuse with the small mass of gray matter called 

 the nucleus amygdalce (JVa). A sagittal (longitudinal dorso-ventral) section 

 taken at some distance from the median line (Fig. 142) shows the curved 

 course of the larger portion of the nucleus caudatus, the extreme head as 

 well as the latter part of the tail lying out of the plane of the section ; and 



