THE CORNEA 303 



most common cause of that condition in man is not the Staphylo- 

 coccus, but the Frankel-Weichselbaum Pneumococcus. 



The earliest researches by culture into the cause of purulent kera- 

 titis did not show this organism, but either gave a negative result or 

 showed Staphylococci and Streptococci. This was due to the same 

 cause as interfered with the etiological study of conjunctivitis and 

 many other infectious diseases namely, that the highly susceptible 

 Pncumococci were only demonstrated when better methods were avail- 

 able. In many of the earlier works on this subject an immediate 

 slide diagnosis was not made. In the corneal pus the encapsulated 

 lancet-shaped Diplococci are very clearly seen. Widmark and Pfluger 

 certainly described appearances which may have been due to the 

 Pneumococcus, but their exact significance remained unknown. 



At the end of 1893 Gasparrini published a paper on the ' Significance of the 

 Pneumococcus in Ophthalmology,' in which, besides giving the results of his 

 experiments on animals, he reported having cultivated the Pneumococcus from 

 several cases of hypopyon-keratitis, mostly in a pure condition. These observa- 

 tions were confirmed and amplified by Basso and Guaita. 



Completely independent of Gasparrini, Uhthoff and Axenfeld began a research 

 on this subject in 1892, and published their results in 1894. They also found a 

 remarkable frequency of the Pneumococcus. In their monograph in the year 1896, 

 in which they reported a series of fifty cases and a number of anatomical investiga- 

 tions, they showed that the bacteriological finding of the Pneumococcus corresponded 

 to that form of hypopyon-keratitis known as 'ulcus corneae serpens,' an ulcer which 

 is characterized by a surface spread especially in one direction so as to form a pro- 

 gressive yellow margin at the same time as it is cleaning and being covered with 

 epithelium from the other side. In the rarer cases which do not present this 

 appearance, but that of an 'atypical hypopyon-keratitis,' with a rapid spread deeply, 

 other pyogenic organisms (Staphylococci, Streptococci, and pyogenic bacilli) are 

 found ; and in this group of the non-serpiginous forms of hypopyon-keratitis we can 

 differentiate sharply an etiologically distinct group the mould keratitis, or keratitis 

 aspergillina. 



Uhthotf and Axenfeld concluded their article by stating that variation of the 

 virulence and number of the organisms, the condition of the nidus (i.e., the pre- 

 existing condition of the cornea), and the depth and extent of the original injury, 

 could cause considerable variation from the typical appearance. Since then they 

 have reported on a further series of sixty-eight cases. In this series they showed 

 that the condition known clinically as ulcus cornese serpens with the exception 

 of one case due to Diplobacilli (probably of the Petit type : vide infra) was alwaj's 

 produced by the Pneumococcus. But they also found, as a matter of fact, that 

 a number of the cases of pneumococcal infection presented an atypical appearance. 

 And for these variations they adduced a number of special reasons. 



Deep wounds (e.g., after cataract operation) when they suppurate show by their 

 appearance that the whole thickness is affected, and when the site of an infection is 

 at the vascular limbus of the cornea, the action is modified, as Bach has shown. 

 The vascularization of the cornea, which takes place, for instance, in pannus 

 trachomatous, furnishes a powerful resistance to the infection, and in such cases we 

 find pneumococcal infection taking on the form of a simple infiltrate, without any 

 dense progressive border. 



