DISEASES OF THE MUSCLES AND TENDONS. 199 



body. The trouble originates, not in a nerve severed, but a 

 nerve injured — bruised, lacerated, or torn. When a nerve 

 is divided by a common, " clean " cut, its action is entirely 

 suspended, and, bye and bye, the parts heal over as naturally 

 as ever. This takes place in all ordinary incised wounds, 

 without producing any serious consequences. But when the 

 nerve is torn or bruised, its action is increased; it becomes 

 irritated and inflamed; and then, should there happen to be 

 any predisposition to fever lurking in the system, there is 

 great danger that tetanus will conclude the history of the 

 case. We are well satisfied that scarcely any possible injury 

 of the nerves will occasion lock-jaw when the general condi- 

 tion of the animal is that of sound health and entire free- 

 dom from fever. 



Let any horse, however, be exposed, and take .cold, after 

 an injury of one of the nerves, such as we have mentioned, 

 and tetanus could not be courted more effectually. Of 

 course, some degree of inflammation must follow the sever- 

 ing or wounding of a nerve in any case ; but if J^ature had 

 nothing more than this to overcome, with all the vital forces 

 in perfectly healthful action, the trouble would very soon be 

 over. If the inflammation, on the other hand, finds a co- 

 operative agency ready to extend and aggravate it, as it 

 does when the blood is in a feverish state, it is carried rap- 

 idly along the nervous pathway to the great sensorium of the 

 body, the brain. From this it reacts in a terrible spasmodic 

 action, in which the tension of the muscles and tendons, in 

 every part and'*organ of the body, is so fearfully great that 

 the horse dies at last, exhausted by hard work. During the 

 progress of the disease, not only are the muscles and ten- 

 dons more and more contracted, but the skin becomes tighter, 

 the joints more stiffened, the breathing still more labored, 

 and the power of motion less and less, until, finally, the poor 

 sufferer falls to the ground, to rise no more. 



The symptoms of tetanus are usually very obscure at the 

 beginning. Were they recognized at the outset, there would* 

 seldom be any great difficulty in applying effectual treat- 



