142 PHILOSOPHY OF ZOOLOGY. 
merous bloodvessels, which likewise penetrate mto the 
brain beneath. 
The brain itself, in the more perfect animals, appears in 
the form of a soft, compressible, slightly viscous mass. It 
exhibits such differences in its texture, as to induce anato- 
mists to consider it as composed of two distinct substances, 
to which they have applied the terms Cineritious and Medul- 
lary. 
The cineritious, or cortical substance, as it is likwise cal- 
led, is of a greyish colour, usually tinged with red, semitrans- 
parent, and, to the eye, appears to be homogeneous. - It 
is soft and vascular in its texture. Injections penetrate its 
substance, and exhibit the existence of bloodvessels. ‘* Its 
quantity, (says Cuvier.) with respect to the rest of the 
brain, decreases in the cold blooded animals. It is propor- 
tionally greater in man than in any other animals.” 
The Medullary matter is of a white colour, opaque, and 
of a firmer consistence than the cineritious. When examin- 
ed with a glass, it appears to consist of fibres disposed in 
different directions. It possesses few bloodvessels, and in- 
jections do not penetrate to all its parts. 
These two substances constitute not only the brain, but 
the spinal marrow and the nerves. They differ from each 
other in relative situation, according to circumstances. In 
the brain the cineritious matter is chiefly peripheral, while 
in the spinal marrow it is central. They cannot be distin- 
guished, with certainty, as existing separately in the ner- 
vous system of the white blooded animals. 
The chemical analysis of brain has hitherto made us but 
imperfectly acquainted with the ingredients of which it con- 
sists, or their peculiar state of combination. According to 
VAuauELIN it is composed of 
