HORSES. 15 



fibrils : these are welded together on the principle of a bundle of 

 sticks, which can bear a greater strain than a solid piece of wood 

 can of the same weight. The ends where tendons and ligaments 

 are attached to bones spread out, fan-like, and thus obtain a 

 wider " insertion," as it is called. A twist or semi-circular 

 movement, when the structure is already " taut," results in 

 a stretching of some fibres or an injury less severe than actual 

 rupture, but still a sprain or strain. 



There is every degree of sprain, from a slight over-extension 

 to absolute division and complete breakdown ; but the principle 

 is everywhere the same, and this is what we wish to make clear. 



There is a class of sprains which to any but surgeons seems 

 quite inexplicable. Such strains are not the result of a drop 

 jump, or a twist, or of a treading upon a stone, nor are they 

 caused by concussion or by any of those means usually classed 

 as accidents, but they are due to muscular fatigue. 



Take an example from the hunter, or the draught-horse 

 fetching sand from the sea-shore. One may be going steadily 

 through deep, soft ground, and the other walking through 

 equally soft but even looser sand. A sprain occurs low down 

 on the leg, and why ? The muscles, owing to fatigue, have 

 failed to contract, and the tendons (which are only the pulleys 

 acted on by muscles) are allowed to remain on the stretch too 

 long. 



Tendons and ligaments, like every other part of the body, 

 derive their nutriment from blood and their sensation from 

 nerves. When a sprain occurs the nerves are stretched or torn, 

 hence the great pain which is caused in severe cases. If the 

 blood vessels are broken, an escape into the substance of the 

 injured member causes rapid enlargement. If only stretched, 

 these vessels are excited and an increased amount of blood is 

 sent to the part ; 



INFLAMMATION IS SET UP; 



the part appears swollen and feels hot. Pain is evinced 

 on pressure ; suffering follows upon exertion. 



