100 THE HORSE. 



nioro; however, is accomplished by this singular mechanism. The eye is 

 naturally deep in the "orbit, that it may be more perfectly defended; but it 

 may be necessary, occasionally, to bring tiie eye forward, and enlarge the 

 field of vision. The eye is actually protruded under the influence of fear: 

 not only are the lids opened more widely, but the eye is brought more for- 

 ward. How can this jwssibly be accomplished ? There are no muscles 

 anterior to, or before the eye — there is no place for their insertion. The 

 object is readily etfccted IJy this singular pulley, h, c. By the power of 

 this muscle, the troch/caris, or pulley-muscle, and the straight muscles at 

 the same time not opposing it, or only regulating the direction of the eye, 

 it is really brought somewhat forward. The lower oblique muscle rises 

 just within the lachrymal bone (/, p. 66), and, {)roceeding across the eye, 

 is fixed into the part of the sclerotica, op])osite to the other oblique muscle, 

 and it turns llie eye in an opposite direction, assisting, however, the uj)per 

 oblique, in bringing the eye forward from its socket. 



CHAPTER VJI. 



TNJURIES AND DISEASES OF THE SKULL— THE BRAIN— THE EARS— 

 AND THE EYES. 



We have now arrived at a convenient resting-place in our somewhat dry, 

 but necessary description of the structure of the horse, and we willingly 

 turn to more practical matter. We will consider the injuries and diseases 

 of the parts we have surveyed. In entering, however, on this division of 

 our work, we would premise, that it is impossible for us to give the farmer 

 such an account of the nature and treatment of the diseases of horses as 

 will enable him with safety to practise for himself, e.xccpt in the commonest 

 cases. The causes of most diseases are so obscure, their symptoms so 

 variable, and their connexion with other maladies so complicated and mys- 

 terious, that a life devoted to professional study will alone qualify a man to 

 become a judicious and successful practitioner on the diseases of the horse 

 and other domestic animals. Our object will be to communicate suflicient 

 instruction to the farmer, to enable him to act with promptness and judg- 

 ment when he cannot obtain professional assistance — to qualify him to form 

 a satisfactory opinion of the skill of the veterinary surgeon whom he may 

 employ, and, more especially, to divest himself of those strange and absurd 

 prejudices which, in a variety of cases, not only produce and prolong dls. 

 ease, but bring it to a fatal termination. 



FRACTURE. 



We have described the cavity of the skull of the horse as being so 

 defended by the hardness of the parietal bones, and those bones as so covered 

 by a mass of muscle, and protected above by an additional layer of bone, 

 and the occipital bone as so exceedingly thick (see cut, p. 68), that a frac 

 TURE of the bones of the skull is almost impossible. It can only occur from 

 brutal violence, except that, when a horse falls in the act of rearing, the 

 occipital bone is sometimes fractured ; when he falls forward, and the head 

 comes in contact with the ground, the muzzle or jaws will receive the 

 principal or whole force of the blow. When, however, fracture of the skuP 

 docs occur, it is almost invariably fatal. A blow of sufTicient violence to 



