302 THE HORSE 



Tetanus, or Lockjaw. 



Tetanus is a stiffening of the muscles, especially of the 

 head and neck, accompanied by more or less spasm, and 

 when once seen can never be forgotten. The microbe 

 which causes it is introduced through some opening in the 

 skin, and as its habitat is generally in the soil an injury to 

 the foot is the usual mode of its entry into the system of a 

 horse. It is said also to have an affinity for iron-rust, and 

 an operation performed with a dirty knife has often been the 

 reason of its making its dreaded appearance. It frequently 

 follows after a prick in the foot from a nail, broken knees, 

 castration, and docking, and usually appears seven or eight 

 days after the injury has occurred. After ten days have 

 passed there is not much fear of tetanus setting in. 



The muscles of the jaws and neck are usually first affected, 

 the animal having difficulty in swallowing and turning its 

 neck ; before long these muscles become quite stiff, the mouth 

 is nearly closed, the jaws cannot be parted, and little food 

 can be taken into the mouth. By degrees all the muscles 

 become affected with the same stiffness and cramp; and 

 amongst the most characteristic signs is the pointing for- 

 wards of the ears, which are erect and fixed, and the staring 

 of the eyes, which are drawn back into the socket, with the 

 haw thrust forward in front ; the head cannot be raised or 

 lowered, and the legs are fixed stiffly and spread out from 

 each other, the tail is lifted up, held straight out, and in a 

 constant tremble, and the lips are firmly stretched across 

 the teeth, which are partly seen. The breathing is 

 quickened, laboured, and convulsive ; the bowels are bound, 

 and the urine is difficult to pass. When convulsions come 

 on and keep increasing in strength there is little hope of 

 saving the animal, but in the absence of these there is a 

 good chance of recovery if the strength can be maintained 

 by careful nursing. The writer has known of a case which 

 lasted six weeks, and the patient eventually got per- 

 fectly well and was able to do its work the same as 

 before. 



As the eyes are extremely susceptible to light, the invalid 



