THE SENSORIAL FUNCTION. 79 



ingly minglinjr, they never run into the same mass, or change by degrees into one 

 another, but are essentially distinct in construction as well as in function. 



The medullary portion is connected with the nervous system. The nerves are pro- 

 longations of it, and are concerned in the discharge of all the offices of life. They 

 give motion 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 cinerilious part has a different appearance, and is differently constituted. Some 

 have supposed, and with much appearance of truth, that it is the residence of the 

 mind — receiving the impressions that are conveyed to the brain by the sensitive nerves, 

 and directing the operation and action of those which give motion to the limbs. In 

 accordance with this, it happens that, where superior intelligence is found, the cineri- 

 lious portion prevails, and where little beside brute strength and animal appetite 

 exist, 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 dog than in llie 

 horse. The additional bulk of brain is composed of cineritious matter; and how dif- 

 ferent is the character of these animals I — 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 cineritious 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, or the motion is effected ; the former is the substance to 

 which that impression 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 reproduction; 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, qualify them for this purpose ; but were propor- 

 tionate intellectual capacity added to this — were they made conscious of their strength, 

 they would burst 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 purposes, in order that intelligence should be added to animal power. 

 Almost every mental faculty, and almost every virtue, too, maybe traced in the brute. 

 The difference is in degree, and not in kind. The one beiug improved by circum- 

 stances, and the other contaminated, the quadruped is decidedly the superior. 



From the medullary substance — as already stated — proceed certain cords or pro- 

 longations, termed nerves, by which the animal is enabled to receive impressions from 

 surrounding objects, and to connect himself with them; and also to possess manv 

 pleasurable or painful sensations. One of them is spread over the membrane of the 

 nose, and gives the 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 an equally important one bestows the power of feelino-. 



One division of nerves, (k, p. 72) springing from a prolongation of the brain, and 

 yet within the skull, wanders to different parts of the frame, for important purposes 

 connected with respiration or breathing. The act of breathing is essential to life, and 

 were it to cease, the animal would die. These are nerves of involuntary motion; so 

 that, whether he is awake or asleep, conscious of it or not, the lungs heave and life is 

 supported. Lastly, from the spinal cord t] — a farther prolongation of the brain, and 

 running through a cavity in the bones of the neck, back, and loins, and extendino- t_ 

 the very tip of the tail — other nerves are given off at certain intervals. The cut at the 

 top of the following page delineates a pair of them. The spinal cord a, is combined 

 of six distinct columns or rods, running through its whole length — three on either side. 

 The two upper columns — the portion of spinal marrow represented in our cut, is sup- 

 posed to be placed with its inner or lower surfvxce toward us — proceed from those 

 tracks of the brain devoted to sensation. Numerous distinct fibres spring abruptly 

 from the column, and which collect together, and, passing through a little o-anglion or 

 enlargement, d — an enlargement of aaiervous cord is called a ganglion — become a 



