THE SENSORIAL FUXCTIO:s'. 151 



W^e now arrive at the brain itself. The brain of the horse corresponds 

 with the cavity in which it is placed. It is a flattened oval. It is divided 

 into two parts, one much larger than the other — the cerebrum or brain, 

 and the cerebellum or little brain. In the human being the cerebrum is 

 above the cerebellum, in the quadruped it is below ; and yet in both they 

 retain the same relative situation. The cerebellum is nearer to the fora- 

 men through which the brain passes out of the skull, than the cerebrum, 

 but portions from each unite to form the medulla oblongata, which passing 

 out of the cavity of the cranium into the spinal canal, becomes the spinal 

 cord. In the human head this foramen is at the base of the skull ; but in the 

 quadruped, in Avhom the head is placed slanting, it is necessarily elevated. 



He who for the first time examines the brain of the horse will be struck 

 with its comparative diminutive size. The human being is not, generally 

 speaking, more than one-sixth of the size and weight of the horse ; yet 

 the brain of the biped is twice as large and as heavy as that of the quad- 

 ruped. If it had been the brain of the ox that had been here exposed, 

 it would have been but two-thirds of that of the horse. If the dog had been 

 the subject, it would have been very considei-ably larger, comparing the 

 o-eneral bulk of each animal. This is sinsrular. The human brain largest 

 in comparative bulk ; then the brain of the dog, the horse, the ox. Thus 

 would they be classed in the scale of intelligence. 



If the brain is more closely examined, it Avill be observed that there 

 is not that roundness and broadness found in the human being ; it is 

 comparatively level and flat. There is, however, sufiicient irregularity of 

 surface — there are projections and depressions to remind us that the 

 phrenological development of the brain of the horse should not be lost 

 sight of — his pride and love of approbation, his acute remembrance of 

 persons and places, his perception of music and time are extraordinary. 

 After the dog, there is no animal endowed with more intelligence than the 

 horse. Were the brain of the beaver, of the hare, or the rabbit, or of almost 

 any bird, substituted for it, there would be no convolutions or irregularities 

 at all. 



The irregularities on the surface of the brain are not so bold and so deep 

 in the ox as in the horse, nor in the horse as in the dog. We do not know 

 enough, as yet, of the functions of the particular portions of the brain to 

 associate those convolutions, accurately, with any particular powers of 

 mind, or good or bad propensities ; though, doubtless, such knowledge will 

 ultimately be obtained. It would occupy two much space fully to enter 

 into these questions ; but there are some diseases to which the horse is 

 subject, for which a very useful operation — the division of some of the 

 nerves — is had recourse to, the eff'ect of which operation could not be 

 understood without a previous slight account of this important organ. 



When the brain is cut, it is found to be composed of two substances 

 very unlike in appearance ; one, principally on the outside, grey, or ash- 

 coloured, and therefore called the cortical (barJi-like) from its situation, 

 and cineritio'us (ashen) from its colour ; and the other lying deeper in the 

 brain, and from its pulpy natru-e called the medidlary substance. Although 

 placed in apposition with each other, and seemingly mingling, 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. We are told by 

 Mr. Solly, in his most valuable work on the brain, that the cineritious or 

 dark portion of the brain is the source of mental power— that is, it is the 

 portion of the brain by means of which the mind or instinct developes itself; 

 that it is collected in masses of variable form and shape, both within and 

 without the brain, called ganglia, and that these ganglia are the immediate 

 means of mental demonstration, while the medullary or white portion 



