70 



THE SENSORIAL FUNCTION. 



Mucn tune spent among horses, an acquired love of them, and a little, sometime* 

 nossibly too dearly-bought experience, may give the agriculturist some insight intc 

 these matters. We will try whether we cannot assist him in this affair whetl er we 

 cannot explain to him the reason why certain points must be good, and why a norse 

 without them must of necessity be good for nothing. Perhaps some useful rules may 

 thus be more deeply impressed upon his memory, or some common but dangerous 

 prejudices may be discarded, and a considerable degree of error, disappointment, and 

 expense avoided. 



If we treat of this at considerable length, let it be remembered that the horse is oui 

 noblest servant, and that, in describing the structure and economy of his frame, we 

 are in a great measure describing that of other domestic quadrupeds, and shall here- 

 after have to speak only of points of difference required by the different services and 

 uses for which they were destined. And further, let it be remembered, that it is only 

 by being well acquainted with the structure and anatomy of the horse, that we can 

 appreciate his shape and uses, or understand the different diseases to which he is 

 liable. It is from the want of this that much of the mass of ignorance and prejudice 

 which exists as to the diseases to which he is subject is to be referred. 



The nervous system will first pass in review, for it is the moving power of the 

 whole machine. It consists of the brain, to which all sensation is referred or carried, 

 and from which all voluntary motion is derived the spinal cord, a prolongation ot 

 the brain, and thus connected with sensation and voluntary motion, governing all the 

 involuntary motions of the frame, and by power from which the heart beats, and the 

 lungs hcare, and the stomach digests ; and one other system of nerves the ganglionic 

 presiding over the functions of secretion and of nutrition, and the repair and the 

 welfare of the frame generally. 



The foil owing cut represents the head of the horse divided into the numerous bones 

 of which it is composed, and the boundaries of each bone clearly marked by the 

 sutures which connect it with those around. 



The upper and broadest part is the cranium or skull in which the brain is con- 

 tained, and by which it is protected. It is composed of nine bones : the two frontals, 

 a a ; the two parietals, c c ; the two temporals, d d ,- the occipital g, and the ethmoid 

 and sphenoid, which will be found delineated at figures k and /, and will be bettei 

 seen in the cut on page 72. 



The frontal bones, or bones of the forehead. 



The supra-orbital foramina or holes above the orbit, through 

 which the nerves and blood-vessels supplying the fore- 

 head pass out. The small hole beneath receives the ves- 

 sels which dip into and supply the bone. 



The parietal bones, or walls of the skull. 



The temporal bones, or bones of the temples. 



The zygomatic, or yoke-shaped arch. 



The temporal fossa, or pit above the eye. 



The occipital bone, or bone of the hinder part of the head. 



The orbits containing and defending the eye. 



The lachrymal bones belonging to the conveyance of the 

 tears from the eyes. 



The nasal bones, or bones of the nose. 



The malar, or cheek-bones. 



The superior maxillary, or that portion of the upper jaw 

 containing the molar teeth or grinders. 



The infra-orbital foramen a hole below the orbit, through 

 which pass branches of nerves and blood-vessels to supply 

 the lower part of the face. 



The inferior maxillary, the lower part of the upper jaw 

 bone a separate bone in quadrupeds, containing the 

 incisor or cutting teeth, and the upper tushes at the 

 point of union between the superior and inferior' maxil- 

 laries. 



The upper incisor or cutting teeth. 



The openings into the nose, with tbe bones forming tht 

 palate. 



