4 BULLETIN 65, U. S. DEl'AKTMENT OJ^^ AGRICULTURE. 



Other names which have been given to this affection are epizootic 

 encephalo-myelitis, meningo-encephalitis and meningo-myelitis, en- 

 zootic cerebri tis, leuco-encephahtis, 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 

 sho^^^l 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- 

 teriological 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 remainsthat 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 Schlogel incriminated a micrococcus as 

 the cause of the disease. On the other hand, Johne found diplococci 

 in the cerebrospinal fluid which he termed Diplococcus 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, refusmg to grow 

 wtII 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 pneumonise. 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 



