264 



ANATOMY OF THE CENTRAL NERVOUS SYSTEM. 



you a series of frontal sections through an adult brain. 

 as a guide in your own investigations. 



They may serve 



For topographical study I advise you to place an entire, uncut brain in 10- 

 per-cent. formol solution {Blum), and, after from four to eight days, to cut it up 

 with a razor into sections about one centimeter in thickness. The illustrations which 

 I here present to you are made from sections prepared in this manner. Here and 

 there an examination in water with the lens will prove advantageous. 



The first section that I make (not shown here) passes a few centimeters behind 

 the frontal pole of the brain. Surrounded by the convolutions, which are here small, 



Sulc. cinguU 



Gyms cinguli - - ^jy^ 

 Cingulum f^ )« 



Corpus callos 



Cingulum 

 Gyrus fornicritua 



Sulc. cinguli 1 

 Ram. marg. J 



Gyri orbital es 



("Fasc. area 

 \ atus 



Ad crus nnt. 

 capsulae 



Pig. 170. 



it contains an homogeneous white mass constituted essentially as follows: Just 

 under the cortex it is composed of short association-bundles; beneath these of the 

 coronal fibers to the thalamus and to the pons (which begin to pass downward even 

 here) ; and^ finally, of the frontal ends of the longer association-systems. 



The second section (Fig. 170) is made a few millimeters behind the beginning 

 of the corpus callosum. It just cuts through the genu of the corpus callosum, the 

 most anterior fibers connecting both hemispheres. A great part of these fibers is 

 cut away laterally; it is those fibers which turn anteriorly in a gentle curve, and 

 thus naturally are chiefly contained in the portion of brain removed. Directly lateral 

 to the fibers of the corpus callosum there is cut the gray substance which surrounds 



