CHAPTER VIII 

 THE CORNEA 



CERTAIN precautions, which have been stated on p. 3, should be 

 taken when we collect material from the cornea for bacteriological 

 examination. I would again mention that the causal organism may 

 escape demonstration on account of its deep situation, as in the 

 case of purulent infections certainly due to organisms. In these 

 cases we should not scrape very deeply or firmly. 



As in the various forms of conjunctivitis, so with regard to the clinical 

 appearances of corneal inflammations due to organismal infection, no 

 absolutely distinct bacteriological types exist. Here, as in the other 

 situation, variations in the susceptibility, the resistance, and the power 

 of reaction of the tissues, the nature and the depth of the injury or 

 epithelial lesion, along with the numbers and the virulence of the 

 bacteria, influence the clinical appearances, and can modify the 

 symptoms to a varying extent. 



Notwithstanding this, it has been established in the pathology of 

 corneal inflammations that the cause of the infection and the clinical 

 appearances, to a certain extent, do correspond; as, for instance, the 

 Pncumococcus most commonly produces an ulcus serpens, the Zur 

 Nedden bacillus appears in the form of an infectious marginal kera- 

 titis, etc. Just as in conjunctivitis clinical diagnosis is the most 

 important, so is it here in the cornea. And for exactly the same 

 clinical reasons must it be supplemented by bacteriology. One and 

 the same infiltrate may have a different prognosis, may require a 

 different treatment, and present different indications for treatment, 

 according to its bacteriological etiology. 



By this I do not merely refer to the attempts at a serum treatment 

 for the ulcus corneee serpens. These attempts have so far led, in 

 only a very limited extent, to anything of value in dealing with 

 the fully-developed disease. 1 The determination of a pneumococcal 



1 Of. Axenfeld, ' Serumtherapie Infectioser,' etc. 

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