118 THE EXTERIOR OF THE HORSE. 



series along the common inferior vertebral ligament. In our opinion, 

 these should be attributed to the violent and continuous pressure 

 of the saddle or the harness. If this be true, it is easily perceived 

 that these excrescences on the body of the vertebrae are most common 

 in animals which, instead of having this region straight, have it 

 strongly concave. 



The first ill effect of this concavity is an overtaxing of the vertebral 

 ligaments due to the displacement of the bones, — a condition which com- 

 municates to the rachidian column a greater flexibility than is physio- 

 logical. The result is that the transmission of the impulsive action of 

 the hind limbs communicated to the anterior part of the body is incom- 

 plete. The region lacks sufficient rigidity, and a certain part of the 

 force is wasted, to the detriment of the speed, since its effect is to 

 deviate the vertebrae from their normal rectitude. 



Sway-backed horses are not adapted to work which exacts much 

 force and resistance of the back. They cannot be employed as hunt- 

 ers, runners, or cavalry horses, but should be reserved to draw vehi- 

 cles, one with four wheels being preferred. 



With M. Bouley ^ we believe, nevertheless, that it is necessary to 

 discriminate between a real concavity of this region and that which 

 is only apparent, — a condition sometimes existing in horses capable of 

 the greatest exertion. The latter appears to be due to a concavity of 

 the superficial surface of the back alone, to a peculiar curvature formed 

 by the series of spinous processes, which may be shorter in the middle 

 of this region than in front or behind. It is a veritable anatomical 

 anomalv. In this case the arch of the vertebrae themselves is in a 

 normal condition and fulfils all its functions. This remark should 

 consequently be taken into account, and a positive judgment should 

 not be expressed unless the proof is apparent. 



It has also been said of horses thus formed that the reaction of 

 the back is less hard than that of the average horse, — a fact which 

 has recommended them to favor as saddle-horses. Some authors, as 

 Curnieu, Eugene Gayot, and Vallon, assert that this last fact is due 

 to a different order of phenomena, which lead to a suppleness and 

 ease of the movements. These result, in this view, not from any 

 peculiar condition of one region alone, but from the conformation of 

 the body as a whole. The latter interpretation is true, but it does 

 not destroy the validity of the other. One isolated cause may produce 

 the same effect as several others combined. 



1 H. Bouley, Nouveau Dictionnaire pratique de m^decine, de chirurgie et d'hygifine v6t6ri- 

 naires, t. v. p. 130. 



