THE BRAIN. 143 
Water, - . - 80.00 
White fatty matter, . . 4.53 
Reddish fatty matter, 7 Stee MD- tO 
Albumen, : = - 7.00 
Osmasome, a = = Lig 
Phosphorus, p e - 1.50 
Acids, salts, and sulphur, 5.15 
100.00 * 
In professor Joun’s examination of the cineritious mat- 
ter of the brain of a calf, he detected the following salts :— 
muriat of soda, a sulphat,—the phosphats of lime, soda, 
ammonia, and magnesia, with a trace of the phosphat of 
iron, and silica +. 
The brain in consequence of its structure, is usually di- 
vided into two portions, termed Cerebrum and Cerebellum. 
The cErEBRuM occupies the whole frontal, coronal, and 
a great part of the occipital portion of the skull. Its peri- 
pheral portion consists of cineritious matter ; its central, of 
medullary, here and there mixed with cineritious. Its 
surface is marked by numerous furrows, of various depths, 
and which are convoluted in different directions. It is di- 
vided longitudinally and vertically, by a deep fissure, which 
receives a duplicature of the dura mater, into two nearly 
equal portions, which are termed Hemispheres. These are 
convex externally, irregular beneath, and flat on the oppos- 
ing surfaces. Each hemisphere is divided into three dobes ; 
the anterior, which rests on the orbital plate of the frontal 
bone; the middle, occupying the cavity formed by the 
sphenoid and temporal bones ; and the posterior, which oc- 
curs nearest the neck, and rests on the cerebellum. In de- 
scending between the two hemispheres, towards the centre, 

* Annals of Phil. iii, p. 27. + Ib. vii. p. 54. 
