SYMPTOMS AND COURSE. 175 



tered at the base of tlie brain and in tlie sacro-lumbar region 

 of the cord. 



Even when the hypera^mia and blood-stasis are not con- 

 spicuous in the vessels of the meninges, the muddy colour of 

 the existing spinal fluid and dull opaque character of the 

 former structures are distinctive. 



In addition to the membranes, the proper substance of the 

 brain and cord are excessively vascular, and may also be some- 

 what softened. 



When pneumonic symptoms have been conspicuous during 

 hfe, the lung-tissue is found congested or inflamed, the solidi- 

 fied structure undergoing in some instances further distinctive 

 changes. 



Symptoms and Course. — In its onset this disease is very 

 often sudden, there being no premonitory indications of illness, 

 the characteristic symptoms at once attracting attention. Im- 

 pairment of motor-power is often so complete and so rapidly 

 developed that the horse falls to the ground in a most unac- 

 countable manner, or this complete disturbance of muscular 

 power may have been shortly preceded by vertigo or staggering, 

 particularly noticeable on moving the animal around, when a 

 disposition is exhibited to twist the hind-feet one over the 

 other, through inability to control the movements. 



When laidon the ground there are ordinarilymuch struggling, 

 and perspiration of a patchy character, pulse and respirations 

 quickened — these disturbances of a very irregular character 

 as respects the relation of the one to the other. In many 

 instances there is marked hyperesthesia, particularly of the 

 anterior parts of the body, with clonic and convulsive con- 

 traction of the superior cervical and dorsal muscles, in some 

 instances passing on to opisthotonos. In the majority, although 

 from the wild appearance of the eyes and injected conjunctiva, 

 with restless tossing of the head, it is evident that the internal 

 cerebral parts are invaded, consciousness is not extensively 

 impaired, and the creature seems acutely sensitive to every 

 impression. 



When the cerebral centres are more affected there are pro- 

 portionate coma, contracted pupils, slower pulse, and stertorous 

 breathing. 



Very early in the affection, and all through the disease. 



