THE BRAIN. 517 
Besides the gray matter, with its cells of highest functional 
value from the standpoint now taken, the brain consists, and 
in large part, of neuroglia and nerve-fibers, with probably 
Fig. 377.—Diagrammatic horizontal section of a vertebrate brain (Huxley). The following 
letters serve for both this figure and the one following. Mb, mid-brain. What lies in front 
of this is the fore-brain, and what lies behind, the hind-brain. L. t, the lamina terminalis ; 
Olf, olfactory lobes; Hmp, hemispheres; Th. E, thalamencephalon ; Pn, pineal gland ; 
Py, pituitary body ; FM, foramen of Munro; CS, corpus striatum ; Th, optic thalamus ; 
CQ, corpora quadrigemina ; CC, crura cerebri; Cb, cerebellum ; PV, pons Varolii; MO, 
medulla oblongata ; J, olfactorii ; IJ, optici ; IZZ, point of exit from brain of motores oculo- 
rum ; IV, of pathetici; VJ. of abducentes } V—XII, origins of the other cerebral nerves. 
alk yey ventricle ; 2, lateral ventricle ; 3, third ventricle ; 4, fourth ventricle ; +, iter 
a tertio ad quartum ventriculum. 
Fia. 378.—A longitudinal and vertical section of a vertebrate brain (Huxley). Letters as 
above. The lamina terminalis is repr: ted by the strong black line between F'M and 3. 
chiefly, and in the case of the fibers solely, a conducting func- 
tion. It will appear that body-weight must be taken into 
account in comparing the brains of the sexes and of indi- 
viduals, Again, the quality or functional capacity of the indi- 
