THE HORSE IN SICKNESS AND DISEASE 281 



the cause. If mechanical injury have occasioned fracture 

 in any part of the spinal column, the case is hopeless. If 

 the injury be less severe, it is possible that extravasated 

 blood only, or serous deposit, or coagulable lym])h are 

 effused into the spinal canal, and disturb the functions of 

 the part ; in which case, topical applications are requisite to 

 encourage an absorption of the obstructing deposit. When 

 the paralysis can be traced to some visceral affection, or to 

 disease of the stomach, kidneys, or bladder, the result is not 

 necessarily unfavourable, although our hopes of a recovery 

 are lessened. We should, in these cases, primarily attend to 

 the exciting cause, if it can be discovered. But when there 

 is loss of sensation without loss of motion, the limbs being 

 cold and the horse insensible that he is in possession of such 

 parts, and moving them only when absolutely forced ; or 

 otherwise, when they are entirely paral3"tic, and yet sensitive, 

 it is probable that the nervous irritation originates within 

 the spinal canal. Here, though w^e may with proprietj?" use 

 external stimulants, there will be but small prospect of 

 success. Of internal remedies, strychnia has been found 

 sometimes useful, in one grain, gradually increased to three 

 grain doses ; and it may be united with other tonics, as 

 gentian, or arornatics. This, with purgatives as required, 

 blisters, sheepskins, or a charge over the loins, has occasion- 

 ally effected a cure, when the paralysis has been confined to 

 the hinder limbs only. 



TETANUS — LOCKED JAW. 



Tetanus differs from other spasms in its permanency, its 

 rigid contraction being rarely alternated with periods of 

 relaxation. Locked jaw, so called from the persistent closure 

 of the mouth, is the result of a morbid irritation of the 

 whole nervous system acting on the brain, and thence by 

 the excitor nerves reflected on the motory nerves. As this 

 irritation is capable of pursuing " a retrograde course along 

 the spinal marrow," a wound in the hind foot or hock is 

 almost as likely to induce a locked jaw as one in the fore 

 foot. 



The first is produced by external injury; the second 

 develops itself from various obscure or conjectural causes 

 acting on the spinal cord and brain. Cold, caused by 

 evaporation; standing still after a severe burst in the 



