112 BACTERIOLOGY OF THE EYE 



operation wounds, with the exception of a few organisms occasionally 

 met with, Staphylococci and xerose bacilli are generally found, often 

 in large numbers. Those other organisms which definitely do cause 

 conjunctivitis as for example, the Pneumococcus do not occur, or 

 are found in isolated cases, and in very small numbers. 



According to my own experience, which agrees with that of Morax, 

 when single examples of the less infectious and rather more facul- 

 tative conjunctivitis organisms are found, especially Pneumococci, 

 Streptococci, influenza bacilli, Pneumobacilti, B. coli, and B. siibtilis, a 

 definite etiological diagnosis cannot be made. In such cases we 

 should certainly take note of the condition, repeat the examination, 

 and consider whether we have to do with an inflammation in the early 

 developing or later regressive stage, when the actual causal agent 

 might not yet have reached, or have already passed, its greatest 

 profusion. From the mere presence of an organism we should not 

 venture on a positive diagnosis. When really pathogenic, at a suit- 

 able stage they will be found in large numbers. When we find them 

 numerous, their etiological significance is so very probable that we 

 can give a clinical diagnosis (e.g., ^neumococcal conjunctivitis); for 

 then the possibility of an error that is to say, that the organisms are 

 purely saprophytic though not absolutely excluded, is certainly very 

 small. It is only very rarely that I have found numbers of Pneu- 

 mococci without well-marked inflammatory reaction, and then only in 

 the stagnant secretion of an everted punctum, after extirpation of the 

 sac or a commencing ectropion, etc., when Staphylococci, xerose 

 bacilli, and sometimes Mic. catarrhalis,' could also be found in 

 enormous numbers. 



Staphylococci certainly can be present in large numbers without pro- 

 ducing any result, and the same may be said of the Bacillus xerosis 

 When either of these two organisms occurs along with other infections 

 e.g., Koch-Weeks, Pneumococcus, etc. they are not generally to be 

 considered as ' mixed infections/ but simply as accompanying bacteria 

 which have no definite influence upon the disease. 1 Taking this view, 

 it cannot be said that ' mixed infections,' in the full sense of the term, 

 are common in simple catarrh, though they are in pseudo-membran- 

 ous forms ; they often accompany trachoma and secondary follicular 

 catarrh. In the most profuse mixtures of organisms which I have 

 ever found in the stagnant secretion of ectropion, etc., the impression 

 was given of a saprophytic overgrowth, and the bacteria were often 

 only casually present. 



1 Cf. 'Symbiosis, 'p. 43. 



