CONFORMATION 159 



twenty, but in no case is there any increase in the number 

 of vertebrae, so that if there is any excess of ribs the 

 vertebrae supporting them are taken from the lumbar group 

 and added to the dorsal series. Thin discs of cartilage are 

 placed between each to serve as buffers, and the spinal cord 

 traverses the whole through a canal in each segment. 

 When an unfortunate accident occurs and a poor horse's 

 back is broken, it is often the case that a vertebra is only 

 cracked across, interfering with the spinal cord. This fre- 

 quently happens when the animal is taking-off at a jump, 

 the muscles, for some reason, making an extra effort to that 

 which had been foreseen and telegraphed from the brain 

 along the nerves ; and the system therefore being unpre- 

 pared for the unexpected exertion, the unlooked-for force of 

 the muscles snaps the vertebra. It may be only a small 

 place which causes the mishap. A tiny ditch will do it if its 

 presence has been concealed, and the horse is galloping at a 

 great pace. To a certain extent it resembles the jar when 

 missing a step on going downstairs in the dark, and we have 

 most of us experienced that unpleasant feeling. In this case 

 we are going, literally, at a foot's pace, and there is no great 

 momentum to add to the mishap, otherwise much greater 

 injury would result than usually ensues. 



The sacral vertebrae, which form the croup, are anchy- 

 losed, that is, are united together in one mass, and form a 

 kind of wedge to the arch, formed by the approximation of 

 the haunch-bones. They are five in number. The pelvic 

 arch, as the united bones of the arch are termed, needs to 

 be very strong and solid, for it is the pivot on which the 

 hind limbs turn, and throw forward the whole weight of the 

 animal. 



The caudal vertebrae are usually fifteen in number, but 

 often vary to the extent of two or three above or below the 

 norma] ; and horsemen are well acquainted with the fact that 

 there are short and long docks in Nature, without recourse 

 to the veterinary surgeon's amputating knife. In these the 

 spinal cord ends as a thread, and there is not much danger 

 in docking a horse, though tetanus (lockjaw) occasionally 

 follows. Still it is always impolitic to interfere with 



