462 MENINGITIS IN HORSES 
Symptoms. A variety of symptoms are reported. Depression 
with symptoms referable to the nervous system, especially the brain, 
are reported. The mild attacks may be manifested by paresis or 
loss of perfect control over the limbs, loss of power over the tail, 
impairment of appetite and some difficulty in swallowing, together 
with areas of hyperemia and reddish-brown discoloration of the 
orbital and nasal mucosz. In other cases paralysis of one or more 
limbs may supervene but without marked fever or coma. 
The more severe forms are ushered in by violent trembling, or by 
stupor, apathy and extreme muscular weakness or actual paralysis. 
In such cases the animal may stagger or fall. The inability to swallow 
is often a marked symptom, the saliva falling in strings from the lips. 
Another common phenomenon is the rigid contraction of the muscles 
of the neck, back and loins, the parts becoming tender to the touch 
and a more or less prominent opisthotonos setting in. Twitching 
of the muscles of the shoulders and flanks may be noticed. Trismus 
is sometimes seen. The breathing is usually rapid and catchy and 
the temperature ranges from 103° to 106° F. The pulse may be 
accelerated and hard, soft and weak, or alternating. The eyes are 
usually violently congested, of a brownish or yellowish-red color, and 
the eyeballs may be turned to one side. Paroxysmsof delirium may 
set in when the animal will push against the wall or perform any of the 
disorderly movements following meningo-encephalitis. Sooner or 
later coma and paralysis supervene and death occurs in from five to 
forty-eight hours. In the most acute cases the animal falls and dies 
in convulsions. On an average the disease lasts from eight to four- 
teen days. In the more favorable cases, improvement may begin on 
the third or fourth day. 
Morbid anatomy. Most writers report lesions of leptomeningitis, 
hyperemia of the brain and spinal cord, with extensive effusion into 
the ventricles and subarachnoid spaces. Petechise and parenchyma- 
tous degeneration of the solid organs of the body are also mentioned. 
In the cases examined by the writer there has been an absence of 
macroscopic lesions in the nervous system and other organs that could 
be detected by a gross examination. 
MacCallum and Buckley have found in the brains of horses dying 
apparently of this disease areas of softening ‘‘in the frontal region on 
each side, anterior to the motor region of the cortex.’ The neighbor- 
ing blood vessels were acutely inflamed, with exudation of leucocytes 
and passage of red corpuscles into the peri-vascular lymph sheath 
