328 BACTERIOLOGY OF THE EYE 



etiology of the herpetic affection of the cornea to which keratitis 

 dendritica belongs. The similarity of these conditions to the inocula- 

 tion keratitis in rabbits, which is produced by the action of the virus 

 of variola or vaccinia, should be noted. It would be of interest to 

 compare the findings in the epithelium in the two conditions. 



Opinions have varied very much concerning the role of micro- 

 organisms in that much-discussed condition, neuroparalytic kera- 

 titis. In opposition to the pure neurotrophic, and the traumatic or 

 desiccation theory, E berth and Balogh emphasize the point that 

 a trigeminal lesion only leads to a depreciation of the epithelium, 

 which, again, allows of the entrance of the organisms, the bacteria being 

 the true cause of the inflammation. According to E. von Hippel, bac- 

 teria are always at work in the purulent cases, but in the others they 

 are not regularly found. Ollendorf, 1 at the instigation of Leber, has 

 gone into the matter again, and came to the conclusion that a kera- 

 titis and that, too, a purulent one can occur in rabbits without the 

 presence of any organisms, and due entirely to desiccation. He does 

 not, however, deny that in man desiccation alone is but rarely the 

 cause, and that in the human eye micro-organisms play a part. 

 Bacteriological examinations above suspicion of fallacy, of cases in 

 man, are very few, and their results vary. Treitel and E. von Hippel 

 found cocci, and Zur Nedden found his own bacillus. 



Ollendorf was quite unable to convince himself that an inoculation 

 keratitis, in cases with lesions of the trigeminal, had any different 

 course than the same keratitis in a normal eye. This is opposed to 

 the views of Krause, Angelucci, Spallita, according to whom the cornea 

 has a lowered resistance in the latter cases. Spallita states that in 

 this respect the sympathetic and the trigeminal are antagonistic ; for 

 extirpation of the sympathetic in the neck raises the resistance, 

 previously reduced by section of the trigeminal, to the normal. 

 This finding requires control. Seydl, on the other hand, has observed 

 neuroparalytic keratitis in cases of sympathetic paralysis. Davis and 

 Hall have lately described bacilli resembling B. xcrosis, which they 

 considered to be of etiological importance in neuroparalytic keratitis. 2 



It is well known that the corneal epithelium of various animals 

 (rabbits and guinea-pigs) is a most suitable medium for the inocula- 

 tion and the growth of the virus of variola and vaccinia (not for that 

 of varicella). 3 



1 A. f. 0., 1900, xlix. , p. 445. Cf. here the whole literature; also Haupt, Inaug. 

 Dissert., Bonn, 1902. 



2 British Medical Journal, January, 1908. 



3 Cf. Salmon, Hoc. de BioL, February 12, 1905. 



