THE CORNEA 831 



bacilli; the conditions are complicated in a way similar to those inter- 

 fering with the use of pneurnococcal serum. Perhaps in ' aggressin 

 immunity ' we may find assistance. 



Behring's diphtheria serum is well known to be an antitoxic serum 

 of the type which does not kill the bacteria themselves, but neutralizes 

 their products of metabolism their toxins by some chemical process, 

 rendering them innocuous. 



That this is so has often been shown in ophthalmology. Diphtheria bacilli can 

 be found on the conjunctiva of persons who have suffered from conjunctival 

 diphtheria, and have been cured by the action of the serum, just as is so often the 

 case in the throat. The bactericidal serum of Wassermann 1 may perhaps accelerate 

 their disappearance. 



The action of the antitoxic sera is comparatively certain, because, 

 in the first place, the serum can be consistently and with certainty 

 standardized by Erlich's method ; and secondly, the combination of 

 the toxin with the antitoxin occurs without any activity of the body, 

 j ust as it would occur in vitro. An active serum of this variety also 

 counteracts the toxins of all diphtheria, whatever their origin. 



2. Serum Treatment for Pneumocoecal Infections. (Ulcus 

 Corneae Serpens.) 



The extraordinarily convincing action of the antitoxic diphtheria 

 serum in animals and its applicability to man assured its immediate 

 use in ophthalmology. 



The conditions are very different in that much more common and, 

 from a practical point of view, much more important infection with the 

 Pneumococcus. Although experimental immunization and treatment 

 with serum had for some time been attempted with relation to man, 

 it was not till the work of Eomer appeared that any notice was taken 

 of them in ophthalmology. They were not incorporated in any form 

 of treatment, because the experiments had produced very little con- 

 vincing result, and also because we were in possession of a very good 

 method of treatment for most of these dangerous cases that of the 

 galvano-caustic and the Saemisch section. On account of the im- 

 mense importance of this infection in ophthalmology, I will shortly 

 review the question of pneumococcal immunity. 2 



1 Cf. Vogelsberger, ' Uber die Anwendung eines neuen Serums bei Diphtheric, ' Disserta- 

 tion, Berlin, 1905. 



2 The full literature is to be found in the article by "\Veichselbaum in ' Kolle mid Wasser- 

 mann Handbuch,' 1903, Bd. v. ; also in Marikowsky, Zent. f. akt., 1904, xxxiv., Ref. 

 S. 481. and Homer (loc. cit.) 



