152 THE SE.XSORIAL FUNCTIOX. 



of the brain, lias the secondary dIUcb of being the conductor of that 

 demonstration to every part of the body, it is not developed in the form 

 of irregular masses or ganglia, but is moulded into the more symmetrical 

 form of nerves. 



The medullarij portion is connected -with the nervous system. The 

 nerves are prolongations of it, and are concerned in. the discharge of all 

 the offices of hfe. They give miotion and energy to the limbs, the heart, 

 the lungs, the stomach, and every part connected with life. They are the 

 medium through which sensation is conveyed ; and they supply the mind 

 with materials to think and work upon. 



The chieritlous part has a different appearance, and is differently con- 

 stituted. Some have supposed, and with much appearance of truth, that 

 it is the residence of the mind — receiving the impressions that are con 

 veyed to the brain by the sensitive nerves, and directing the operation and 

 action of those which give motion to the limbs. In accordance wdth this, 

 it happens that, where superior intelligence is found, the cineritious por- 

 tion prevails, and where little beside brute strength and animal appetite 

 exists, the medullary portion is enlarged. There is, comparing bulk with 

 bulk, less of the medullary substance in the horse than in the ox, and in 

 the dcg than in the horse. The additional bulk of brain is composed of 

 cineritious matter ; and how different is the character of these animals ? — 

 the sluggish, stupid ox, and the intelligent horse ; the silly sheep, and the 

 intellectual companionable dog ! 



In a work like this, it would be somewhat out of place to enter deeply 

 into any metaphysical speculation ; but the connexion between the cineri- 

 tious part of the brain and the intellectual principle, and that between the 

 medullary portion and the mere animal principle, do seem highly probable. 

 The latter is the medium through which the impression is conveyed, oi' 

 the motion is effected ; the former is the substance to which that impres- 

 sion is referred — where it is received, registered, and compared, and by 

 which the operation of the motor nerves is influenced and governed. 



The cortical substance is small in the quadruped ; for in their wild state 

 brutes have no concern and no idea beyond their food and repi'odiiction ; 

 and in their domesticated state they are destined to be the servants of man. 

 The acuteness of their senses, and the preponderance of animal power, 

 qvialify them for these purposes ; but were proportionate intellectual capa- 

 city added to this — were they made conscious of their strength, they would 

 bui'st their bonds, and man would, in his turn, be the victim and the slave. 

 The cortical part is found in each in the proportion in which it would 

 seem to be needed for our purpose, in order that intelligence should bo 

 added to animal power. Almost every mental faculty, and almost every 

 virtue, too, may be traced in the brute. The difference is in degree, and 

 not in kind. The one being improved by circumstances and the other 

 contaminated, the quadruped is decidedly the superior. 



From the medullary substance — as already stated — proceed certain 

 coi'ds or prolongations, termed nerves, by which the animal" is enabled to 

 receive impressions from surrounding objects, and to connect himself with 

 them ; and also to possess many pleasurable or painful sensations. One of 

 them is spread over the membrane of the nose, and gives tlie sense of 

 smell ; another expands on the back of the eye, and the faculty of sight 

 is gained ; and a third goes to the internal structure of the ear, and the 

 animal is conscious of sound. Other nerves, proceeding to different parts, 

 give the faculty of motion, while equally important ones bestow the power 

 of feeling. 



One division of nerves spiinging froni a prolongation of the brain, 

 wanders to diiferent parts of the frame, for important purposes connected 



