THE CORNEA 307 



why the organisms are often only to be demonstrated when the 

 material is taken from the deeper layers. 



To facilitate cultural diagnosis, Romer recommended that the 

 Pneumococci should be augmented, so that smaller numbers could 

 be more readily seen ; he did this by cultivating the material in a 

 bouillon, to which one-third of its volume of sterile rabbit s serum had 

 been added. 



Large numbers of phagocytes have been found in severe cases, justi- 

 fying the opinion that in this process, just as in fatal cases of pneumo- 

 coccal meningitis, large numbers of phagocytes may be found. The 



- v *^. - - ^ 



_ * " .~*~ ..*.*- - - r*^. ;- ~--i x_*~ *- 



1 * ..7 . .**TL _ **--' ~ <w "" > "* .rCJWiL- . ~ *'*~ "^ - - 



\ - i . " *" -%* . . ^Wtt - *" 



. ~"1* .*. .^ ,J~ .- * ^ - * -- .1***^ - .*j 



FIG. 66. PNEUMOCOCCI IN THE HUMAN CORNEA. PROGRESSIVE BORDER. 

 GRAM-WEIGERT STAIN. PNEUMOCOCCI BLUE. 



possibility, however, cannot be excluded that active Pneumococci may 

 have spread into a part of the cornea which until then was quite 

 healthy. Zur Nedden states that after a Saemisch section he found 

 the healing process going on parallel with the phagocytosis. 



The beneficial influence of paracentesis in the course of an ulcus 

 serpens certainly depends on the fact that, after the rupture of 

 Descemet's membrane, bactericidal elements can freely pass forwards 

 at the same time that the nutrition of the cornea is improved. The 

 Pneumococci then rapidly begin to show marked involution changes, 

 and cultivations can only be obtained for a short time. The purulent 



202 



