THE BRAIN AND ITS MEMBRANES. 



198 



6. The fifth layer. The line of demarcation between this and the 

 fourth layer is feebly shown; but, on close attention, it will be ob- 

 served that the small cells of the fourth layer rather abruptly give 

 place to elongate ones, not unlike those of the third stratum. The 

 nerve-bundles are here more plainly indicated. 



7. The white matter. (The ganglion cells here cease, and the field 

 is occupied with medullated fibres and neuroglia, the spherical nuclei 

 of the latter becoming prominent from the deep haema. staining.) 



FIG. 134. VERTICAL SECTION OF CEREBRAL CORTEX. SUPERIOR FRONTAL CONVOLUTIO N. X 250. 



A. Arachnoid. 



B. Pia mater. 



C. D, E, F, G. First, second^third, fourth, and fifth layers of gray matter. 

 H. White brain substance. 



8. The nutrient blood-vessels. (The capillaries projected from 

 the pia are especially to be noticed, often of the diameter of a single 

 blood-corpuscle, and presenting as branching lines, composed of these 

 elements indeed difficult of demonstration when empty. Note the 

 light, perivascular lymph-spaces, well seen around the larger arteries in 

 transverse section.) 

 13 



