142 PHILOSOPHY OF ZOOLOGY. 



nierous bloodvessels, which likewise penetrate into 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 

 VAUQUELIN it is composed of 



