I^'JURIES AND DISEASES OF THE SKULL, &,c. 93 



more perfectly defended ; but it may be necessary occasionally to bring it forward, 

 ard 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 forward. 

 How is this accomplished'? There are no muscles anterior to, or before the eye — 

 there is no place for their insertion. The object is readily effected by this singular 

 pulley, i, c. By the power of this muscle — the trochlearis, 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 lacrymal bone (r, p. 70), and, proceeding across the eye, is fixed into the 

 part of the sclerotica opposite to the other oblique muscle, and it turns the eye in a 

 contrary direction, assisting, however, the upper oblique in bringing the eye forward 

 from its socket. 



CHAPTER III. 



INJURIES 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 neces- 

 sary 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 impos- 

 sible for us to give the farmer such an account of the nature and treatment of the dis- 

 eases of horses as will enable him with safety to practise for himself, except 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 mysterious, 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 sufficient instruction to the farmer to enable him 

 to act with promptness and judgment 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 him of those strange and absurd 

 prejudices which in a variety of cases not only produce and prolong disease, 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 so covered by a mass of muscle, and 

 the occipital bone as so exceedingly thick (see page 92), that a Fracture of the skull 

 is almost impossible. It can only occur from brutal violence, or when a horse falls 

 in the act of rearing. When, however, fracture of the skull does occur, it is almosi 

 invariably fatal. A blow of sufficient violence to break these bones must likewisfc 

 irreparably injure the delicate and important organ which they protect. 



The ridge, or outer and upper part of the orbit of the eye, is occasionally fractured. 

 It happens from falling, or much oftener from violent blows. The slightest examina- 

 tion will detect the loosened pieces ; but a professional man alone can render effectual 

 assistance. . 



Mr. Pritchard, in the second volume of the " Veterinarian." relates an interesting 

 case of fracture of the orbit of the eye. " A chestnut mare."' he says, '• received a 

 blow which fractured the orbit from the supercilian' foramen, in a line through the 

 zygomatic processes of the temporal and malar bones to the cuter angle of the eye. 

 The detached bone, together with the divided integument, hung over the eye so as to 

 intercept vision. On examining the place where the accident occurred, two portions 

 of bone were found belonging to the orbital arch. After carefully inspecting the 

 wound, and finding no ether detached portions, nor any spiculse which might irritate 



