Common Diseases of the Horse 173 



On attemptinpr to back an affected animal the tail is sharply raised, 

 and has the same quivering movement, or, as it is sometimes called, 

 the "pump-handle" movement; this being a sudden and spasmodic 

 raising of the tail muscles at each step taken in a backward direc- 

 tion. Various degrees and different forms of the disease are known. 

 The most common type is what may be described as an "ordinary" 

 shiverer, which, when backed, causes the muscles of the quarter to 

 be thrown into a quivering spasm and the tail shot out with the 

 same quivering movement, or lowered and raised at each step, 

 with a pump-handle-like action. This kind of animal, when put 

 to work, is in the great majority of cases quite unable to back its 

 load, and therefore is useless as a shaft horse. When put into 

 chains, however, it will be able to walk ahead and perform this 

 class of work practically the same as if not affected. There are, of 

 course, exceptions, and numerous instances have occurred in which 

 horses, although confirmed shiverers, were quite able to do all that 

 was asked of them more or less as if they were perfectly sound. 



Shivering of this nature commonly affects both hind quarters, 

 but occasionally only one quarter is affected. It may be most 

 marked and easy to see, or, on the other hand, it may be extremely 

 difficult to diagnose, so much so that the expert has to carry out 

 a series of experiments before satisfying himself of its existence or 

 absence. To test a " shiverer", particular notice should be taken 

 of the first backward movement in the stall after the animal has 

 been at rest for some time. The observer should stand at the side 

 of the horse on a level with the quarters and tail, and any slight 

 tremors in the regions indicated should be viewed with the utmost 

 suspicion, particularly if accompanied by any raising of the tail. 

 Further confirmation should then be sought by getting a man, pre- 

 ferably a blacksmith, to pick up the hind leg as in shoeing, extend 

 the limb as far back as possible, when the muscles of the quarter 

 will be found to quiver or shiver. Both hind legs should be raised, 

 as there may exist what is called a " one-sided shiver". 



Accompanied by spasms of these various muscles and shooting of 

 the tail, there is an all-round stiff movement about a shiverer when 

 it is backing. It frequently does so in what is known as "all of 

 a piece", and appears to drag himself back with the hind legs stiff, 

 and if pushed violently may even fall down. Such a horse does 

 not step back with that free-and-easy movement and bending of 

 the knees and hocks which are the attributes of soundness. An- 

 other and much rarer form of shivering is that which is found in the 

 fore limbs, and the horse is then known as a "fore-end" or " front 

 shiverer". 



