SPECIAL FORMS OF CONJUNCTIVAL INFECTION 167 



with the Pnenmococcns. How far the Diplobacilli are ' drought 

 resisting ' has still to be determined. 



The reaction of pure cultures to zinc solutions of varying strengths 

 is naturally of interest, considering the extraordinary beneficial in- 

 fluence which that salt has on the condition of the conjunctiva and 

 the cornea when infected by Diplobacilli. Paul found that when a 

 pure bouillon culture was dried in small reagent glasses, it could with- 

 stand the action of a to 1 per cent, zinc solution for a considerable 

 time, even five minutes. It was really only after a half to one hour's 

 action that any definite anti-bacterial effect could be demonstrated. 

 As it is quite impossible for so strong a solution to remain for such a 

 time in contact with the conjunctiva, Paul concluded that the action 

 was not a simple disinfection. 



Silva has further worked at this subject in my laboratory. 



Silva first experimented to determine whether by continued instillations of weak 

 solutions the zinc could pass into the anterior chamber. The curative action in- 

 fluences even deep purulent infiltrations, and it appeared that the zinc had pene- 

 trated into the tissues. No passage of zinc into the aqueous could be determined 

 with the finest chemical tests, even after removal of the epithelium. 



A ^ per cent, zinc solution had very little lethal (disinfecting) action on cultures 

 of Diplobacilli, but it did prevent development. Its curative action, according 

 to Silva, was due to its power of restraining growth and preventing reinfection. 

 With this assistance the conjunctiva and cornea were enabled to overcome the 

 infection. 



Conjunctival secretion dried on linen swabs for twenty-four days, 

 retained living Diplobacilli which could be cultivated (Erdmann). 

 Such a secretion twenty-five hours old still produced a typical diplo- 

 bacillary conjunctivitis when introduced into the conjunctiva. When 

 dried on glass rods, they grew on the medium after seven hours, but 

 not later. At room temperature the time was longer than when they 

 were in the incubator, as in the latter case complete dryness occurred 

 sooner. 



Diplobacille Liquefiant of Petit. 



(Cf. PLATE III., FIG. //.) 



The previous description refers to the typical Diplobacilhis, the cause 

 of conjunctivitis, as first given by Morax and Axenfeld. 



In 1898 Petit described a very closely allied bacillus, whose relation- 

 ship to the Morax-Axenfeld organism will now be considered. 



He found a Gram-negative Diplobacittus in three cases of superficial 

 serpiginous hypopyon-keratitis with very slight pain (perhaps a case 

 by Uhthoff and Axenfeld was of the same class). The organism 



