118 VETERINARY MEDICINE AND SURGERY. 



Etiology. — The causes are not clearly settled, but the disease is sup- 

 posed to be due to a specific poison existing in the air. Well-fed and 

 high-bred animals are quite as often attacked as others. 



Symptoms. — The symptoms may approach gradually, and this is by 

 far the less fatal form. The horse will at first be noticed to be dull and 

 have a staggering gait, with more and more paralysis, usually of the 

 hind extremities. This extends over from one to three days, when the 

 coma, generally not deep, comes on. The animal is comparatively easily 

 roused, and unless a relapse occurs, the case almost always does well, as 

 far as the acute attack is concerned, but the paralysis which follows this 

 form is, in old horses, apt to be obstinate. Eelapse may occur at any 

 time daring the first six or eight days, or even later, and may i^rove 

 fatal to a case which seems to be doing nicely. 



Occasionally the horse is seized with all the suddenness of a spasm. 

 The muscles of the neck, but especially those of the hind quarters, be- 

 come corded, fixed, and rigid, and soon grow deathly cold to the touch. 

 This tetanic state of the muscles may last some hours, giving Avay finally 

 to flaccidity of the whole muscular system, complete anaesthesia, coma, 

 and death in from twelve to seventy-two hours. Secondly, and this is 

 the most common form in which the disease appears, there are premoni- 

 tory signs, such as rigors, dulness of the eyes, and lassitude of the whole 

 system; followed in from three hours to dfe many days by paralysis, 

 general or partial, more commonly the latter, generally affecting the 

 muscles of the loins and hind extremities, more or less coma accompany- 

 ing this stage. In some few cases delirium has ensued. The jDatient is 

 frantic, beating its head against the wall or floor, as the case may be, 

 with great violence, uttering the most horrible cries, and soon dying in 

 great agony. In such cases recovery is so rare that it is best to destroy 

 the animal. 



The 2ndse during the first few days is not materially altered. 



Temjierature of the surface of the body is lower than in health. 



The hoivels are generally constipated, but may be unaffected or even 

 loose, and in rare cases the fgeces may be passed involuntarily. This is 

 said never to be seen except in fatal cases, and within twelve or fifteen 

 hours of death. 



TJie urine in appearance is generally normal, and passed without 

 difficulty; indeed, incontinence is not uncommon, especially in mares. 

 It may be retained from paralysis, in which case it is, when drawn. 



