68 MANUAL OF EQUINE MEDICINE. 



the superior cervical and dorsal muscles, passing in some 

 cases to opisthotonos. 



In most cases, although the wild look of the eyes and 

 injected conjunctivae indicate that the cerebrum is affected, 

 yet consciousness is not usually impaired. When, however, 

 the cerebrum is more deeply affected, coma with slow pulse 

 and stertorous breathing follow. The bowels are con- 

 stipated ; the urine is often suppressed, and there may be 

 incontinence, especially in mares. Pressure over the spine 

 causes pain. The temperature is variable. It may, or may 

 not, be elevated, and is intermittent. 



In mild cases, which may be met with at any time during, 

 but usually occur towards the close, of an epizootic, the lead- 

 ing symptoms are not so quickly developed. There may be 

 pulmonary complications in this fever, and when this occurs 

 the danger is increased. Priapism in horses and oestrum in 

 mares are of frequent occurrence. 



Morbid Anatomy. — Pathological 'lesions are especially 

 marked in the membranes of the brain and spinal cord, 

 which are found highly congested. The fluid of the sub- 

 arachnoid space is turbid, and increased in amount, and all 

 the vessels of the brain and cord are often congested. 



In many cases patches of ecchymoses are found on the 

 dura mater. 



Prognosis. — If the symptoms come on slowly, the prog- 

 nosis is, as a rule, correspondingly less grave. The number 

 of fatal cases is large, and so the prognosis should always 

 be guarded. The mortality maybe as low as 10 or reach 

 as high as 70 per cent., or even higher. 



At the beginning of an epizootic the percentage of 

 fatal cases is said to be higher. Even when a case is 

 apparently progressing favourably, a relapse may occur. 



Treatment. — If practicable, it is advisable to sling the 

 animal as early as possible. The extremities should be kept 



