126 BACTERIOLOGY OF THE EYE 



who are affected, however, a more important determining factor is the 

 influence of some other local irritation, or a lowered tissue resistance 

 due to injury. 



Cramer, having extensive material, showed how a pure mechanical lesion of the 

 lids at birth had an influence in determining an ophthalmia neonatorum. 



Lobanow infected the conjunctive of rabbits, under various conditions, with 

 Staphylococcus pyogenes aiireus, Streptococci, &nd Pneumococci, and demonstrated 

 that a more severe inflammation resulted if the lid movements were prevented ; 

 the same occurred if the canaliculi were closed or the palpebral fissure narrowed. 

 An increase in the secretion of tears had no influence, so that an actual bactericidal 

 action of the tears could be excluded. If the epithelium was removed from the 

 conjunctiva, then a purulent keratitis resulted. 



Komer proved that the action of various sterile forms of dust (coal dust, grinders' 

 dust, dust from wool, from wood, from tobacco, street dust) increased the flora of 

 the conjunctiva to a very great degree. From its mechanical, and in the case of 

 tobacco its chemical action, the dust produced a hyperaemia and secretion ; twice 

 in 100 cases a purulent conjunctivitis resulted, probably owing to the particles 

 wounding the epithelium, so that an infection with Staplujlococci could occur. 



To decide what conditions were necessary for this dust infection, Komer intro- 

 duced anthrax bacilli, with spores and dust mixed, into the conjunctival sac. Only a 

 few animals contracted an inflammation and general infection. If, however, after 

 introducing the material, he rubbed the eye a few times through the closed lids, 

 then infection occurred more often. This shows that the conjunctiva can be the 

 point of entrance for anthrax. Anthrax spores, when introduced with dust into the 

 conjunctival sac, can after seven days be still found there in a virulent condition ; 

 it must therefore be presumed that when bacteria are mixed with dust particles 

 they are not always washed down the nose, but remain for a considerable time in 

 the conjunctival sac. 



These experiments of Romer's with dust bring out some points of 

 importance in the incidence of conjunctivitis in man ; they show how 

 very slight injuries and chemical irritation make the conjunctiva sus- 

 ceptible. 



In many cases an irritated condition of the surrounding parts pre- 

 disposes to the occurrence of an infection. Acute and chronic in- 

 flammations of the nose and surrounding parts must here be considered, 

 partly because they cause a hyperaemia, with obstruction to the tears, 

 and also because the conj unctiva can be infected from the nose (cf. the 

 chapter on ' Diplobacillary Conjunctivitis,' ' Scrofulous Inflammations,' 

 ' Trachoma,' ' Sac Affections,' etc.; also the article by Gutmann, Deutsche 

 Med. Wocli., 1907, S. 845). 



How does infection occur in the human conjunctiva when there is 

 no such irritation e.g., when it is inoculated from a bouillon culture ? 

 Does the lid pressure drive the bacteria in? Are the pathogenic 

 organisms alone taken up by the conjunctiva, which they damage, on 

 account of special affinity, or are the others taken up also, but have 

 no action? How do the epithelial cells manage to take up the 



