SRE Se 
4 BULLETIN 65, U. S. DEPARTMENT OF AGRICULTURE. 
Other names which have been given to this affection are epizootic 
encephalo-myelitis, meningo-encephalitis and meningo-myelitis, en- 
zootic cerebritis, leuco-encephalitis, etc., but the writer prefers the 
old-fashioned terms cerebrospinal meningitis for the scientific term 
and ‘‘blind staggers”’ for the lay term. That the symptom of stag- 
gering is one of the most common mainfestations of the disease is 
shown by the clinical observations of Schmidt, who has made a close 
study of 415 cases, 377 of which developed staggering symptoms 
while standing or walking. The only symptom which occurred more 
frequently was the loss of appetite appearing in 410 animals, while 
the symptoms next in prominence were grinding of the teeth, which 
was observed in 349 cases, and difficulty in swallowing, which occurred 
in 335 cases. 
ETIOLOGY. 
Unfortunately no specific bacteria, fungus, virus, or other toxic 
principle has yet been found which can be considered as the cause 
of cerebrospinal meningitis in the horse. It is quite true that bac- 
tericiogical investigation has given us a number of different organ- 
isms by an equal number of different investigators, each of whom 
has thought his particular organism to be the causative agent of the 
disease; but the fact remains that the four rules laid down by Koch 
have not been met with sufficient regularity to make the results 
satisfactory to the disinterested worker. Further investigations are 
necessary to decide which, if any, of the reported organisms is the 
true cause of the disease. That the disease may not have an etio- 
logical entity has been suggested by Weichselbaum, Hutyra, and 
Marek. This would seem quite probable if all the claims for the | 
following different etiological factors were to be accepted. For 
instance, Siedamgrotsky and Schlegel incriminated a micrococcus as 
the cause of the disease. On the other hand, Johne found diplococci 
in the cerebrospinal fluid which he termed Dziplococcus intracellularis 
equi. Again, Ostertag recovered streptococci in short chains from 
the blood, liver, urine, and brain of affected horses. These organ- 
isms he termed Borna streptococci. Harrison of Canada isolated a 
streptococcus from the brains of horses affected with cerebrospinal 
meningitis which was quite similar to Ostertag’s, although it differed 
in forming capsules, staining by Gram’s method, refusing to grow 
well on gelatin, and in proving virulent for laboratory animals. In 
Minnesota, Wilson and Brimhall have also incriminated a diplococcus 
as the cause of cerebrospinal meningitis of horses, cattle, sheep, and 
pigs, and proved it to be the Diplococcus pneumonie of Frankel. 
They likewise claimed to have isolated the Micrococcus intracellularis 
meningitidis of Weichselbaum from the central nervous system of a 
cow showing symptoms of spinal meningitis. This latter organism 
