26 BACTERIOLOGY OF THE EYE 



Wolkowitsch emphasizes the fact that in one and the same individual the 

 flora varies at different times of the day. This cannot be wholly denied ; 

 variations in the surroundings and in occupation are here of considerable 

 importance. 



We must, however, always remember that in the comparisons of flora, it is 

 not feasible to make absolutely similar inoculations. It would only be possible to 

 come to any conclusion if throughout a long series the variations were always the 

 same. Changes in surroundings, occupation, and cleanliness can certainly influence 

 the flora of the conjunctiva to this extent at least that the idea of a 'normal 

 conjunctiva,' as applied to hospital out-patients, recruited from the labouring 

 classes, does not convey the impression which the pale, delicate mucous membrane 

 seen in many private patients does. In the former a certain redness is very 

 common, without being called pathological. A combination of a dusty atmosphere, 

 even though not very full of Bacteria, with deficient personal cleanliness, and allied 

 conditions, can produce an increase in the flora in the one class, and we must not 

 be misled by the fictitious appearance of sterility in the pale conjunctivas of the 

 other. A. Fick found in normal school-children far fewer organisms than in the indo- 

 lent inmates of a hygienically unfavourable charity school. If all slightly hypersemic 

 cases are excluded, Diplobacilli will be less frequently found in the ' normal ' con- 

 junctiva than was the experience of Erdmann and Eymowicz. The cases excluded 

 are diplobacillary conjunctivitis of very mild degree. 



2. The method of examination 'which is used is of great importance in 

 determining the bacteria present. 



With regard to the collection of material : 



Morax dropped bouillon or melted gelatine into the conjunctival sac ; this was 

 allowed to soak into the folds of the membrane, sucked up into sterile pipettes, and 

 inoculated on to the media. A much greater extent of conjunctiva was thus avail- 

 able than when the everted membrane was merely rubbed over with a platinum 

 loop. On the other hand, the fluid more readily came in contact with the lid 

 margins, the caruncle, and the inner canthus, so that the specimen was only a pure 

 conjunctival one when the greatest care was exercised. Material taken from the 

 inner canthus shows a considerably greater flora than is found in the conjunctiva 

 itself. Further, it is doubtful if infected epithelial cells will come away with the 

 fluid, while they can readily be rubbed off the surface with the loop. Bacillus 

 xerosis, for example, clings to the desquamating epithelial cells, and thus is much 

 more readily obtained when the loop is rubbed over the surface than when it only 

 lightly touches it or merely removes the tears. The size of the loop and its shape, 

 whether in a single or double twist, are to be considered. As, of course, only a small 

 portion of the conjunctiva comes in contact with the loop, a negative result in 

 cultures is not necessarily to be taken as a proof that the particular membrane is 

 free from organisms. The loop, therefore, preferably bent double, should be well 

 rubbed over the surface without contact with the margins or angles of the lids, and 

 several attempts should be made from different positions. When this method is 

 adopted, a sterile conjunctiva is practically never found ; and should such 

 a finding occur, the next examination will probably show the presence of 

 organisms. 



also raised the temperature). De Lieto-Vollaro obtained the same result when the lids 

 were simply closed under a Fuch's wire frame, and Schirmer has proved by definite 

 examination that when the blinking of the lids is prevented the passage of Bacteria into 

 the nose does not occur. 



