796 VETEEINAEY HYGIENE 



yet in the large majority of cases it is not due to any 

 inborn determination on the part of the animal to be 

 alarmed at anything unusual, but is, in the majority of 

 eases, an uncontrollable weakness due to a peculiar 

 temperament. 



As regards defects in vision these may be due to 

 nutritive changes in the lens or to errors of refraction. 

 Though cataract is generally believed to produce shying, 

 yet the small circumscribed cataract so common in the 

 horse does not affect the sharpness of the image on the 

 retina. On the other hand, errors of refraction like 

 myopia or astigmatism, especially the latter, will certainly 

 cause a blurring of the image sufficient to produce shying. 

 As we have shown,* both myopia and astigmatism are 

 common errors of refraction in the horse, though the 

 amount is generally small. 



The chief causes of shying among horses are due to 

 (1) unusual objects, (2) common objects out of place. 

 Among unusual or terrifying objects are traction-engines, 

 motor-cars, motor-cabs and omnibuses, or electric trams. 

 With reference to these latter, few horses shy at cabs, 

 omnibuses or tramcars which are horsed, but when driven 

 by a motor they are frequently an object of terror. In 

 days gone by the bicycle was a cause of great alarm, but 

 they have become far too common for any but a small 

 majority of horses to take notice of them. In the East 

 camels and elephants are most alarming to horses, and we 

 have known the camel to be an object of alarm to an 

 elephant. Few horses take any serious notice of trains, 

 though there are very few outside big cities which can be 

 trusted to pass under a bridge or viaduct with a train 

 passing overhead. 



Common objects out of place are by far the most frequent 

 cause of shying. There are very few horses that would 

 pass a truss of hay or straw lying in the middle of the road 

 without shying at it, yet, if the animal possessed a shred 



* ' The Kefractive Character of the Eyes of Horses ': Proceedings of 

 the Boyal Society, vol. Iv., 1894. 



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