4IO Veterinary Medicine. 



Micro-biology. It will be recognized that none of these 

 causes fully account for the specific and recurrent nature of 

 this affection, and it is felt that something more is wanted to fur- 

 nish a full and satisfactory explanation of the malady. This 

 explanation is sought in a direct infection, but in spite of ex- 

 tended investigations b}^ many observers no specific microbe has 

 been demonstrated as uniformly present in all cases. 



Potapenke found in the blood of the affected horses a Plasmo- 

 dium like that of ague. This agrees with the damp regions in 

 which the malady prevails and no less with its intermittent or 

 periodic character. 



Vigezzi found in the aqueous and tissues a micrococcus (oph- 

 thalmo-coccus) which, cultivated on gelatin agar and inoculated 

 in the anterior chamber or under the conjunctiva, produced an 

 affection which he recognized as recurrent ophthalmia. 



Trinchera found in the aqueous of the affected animals a ba- 

 cillus and cocci. Drawing this aqueous into a sterilized syringe 

 and injecting it into the anterior chamber of sound horses pro- 

 duced in 12 to 48 hours characteristic periodic ophthalmia. This 

 was repeated by Schiitz and Schwartznecker. 



Robert Koch found in the affected aqueous, cocci, singly or in 

 chains and bacilli with rounded ends. Injection of the latter into 

 a sound horse's eye led to characteristic inflammation and loss of 

 vision. In the cornea of the rabbit it had no effect. 



Richter found in the eyes of a foal born with recurrent oph- 

 thalmia, of sound parents, diplococci and triplococci. 



These observations do not demonstrate the constant presence 

 of one definite microbe, nor that the disease is invariabl}' due to 

 any one particular organism, yet they may be held as strongly 

 suggestive that any one of a variety of microorganisms may 

 prctve an exciting etiological factor in a susceptible system, or 

 that, along with the organisms heretofore demonstrated, there 

 exists an essential microbian cause which has up to the present 

 eluded detection. 



Other points which give circumstantial support to the microbian 

 theory may be shortly stated : 



I. The recrudescence of the disease after its various intermis- 

 sions, and its preference for low, damp, cloudy localities seem to 

 ally it to the malarial diseases of man. 



