362 BACTERIOLOGY OF THE EYE 



of congenital syphilitics, though not in cases of marked interstitial 

 keratitis. 1 Reis was unable to demonstrate their presence in the 

 cornea of a new-born syphilitic suffering from keratitis annular is 

 parenchymatosa. 



The inoculation experiments on the cornea of the rabbit (cf. section 

 ' Syphilis,' p. 357) indicate that the Spirocliatce can settle clown in a 

 cornea which is still intact clinically, just as can the lepra bacilli. 

 Different conditions obtain for these pathogenic agents than are present 

 in the case of the pyogenic. The lepra bacilli (and perhaps also the 

 B. tuberculosis) can leave the vessels and spread into the avascular 

 cornea without the localizing action of an inflammation, and without 

 producing any changes at the site of entry. These organisms appear 

 to be able to collect in a cluster in the transparent tissues, and thus 

 form, away from the margin, a nodular opacity, which later becomes 

 vascularized. This condition is especially associated with a toxic 

 action from the aqueous, corresponding to that obtained in the experi- 

 ments of Leber, Mellinger, and others who produced deep inflamma- 

 tion of the cornea by injection of toxic material into the anterior 

 chamber, and also by mechanical irritation of the endothelium. 



Stock has shown that parenchymatous inflammation can occur from 

 the toxic action of the infected aqueous ; in his experiments tubercu- 

 losis of the iris was accompanied by a simple inflammatory infiltration 

 of the cornea. It remains to be seen to what extent this is the case 

 in man, and whether, in those cases where there is no diffuse cloudi- 

 ness, but only a well-marked deep keratitis, we really have to do with 

 a corneal infection. Elschnig's researches 2 regarding recent keratiiis 

 parenchymatosa syphilitica show that the central, deeply-placed 

 infiltrates need not have any connexion with the anterior chamber. 



We can quite understand how motile organisms e.g., Spirochata 

 can wander in and concentrate in the avascular cornea. It is more diffi- 

 cult to explain in the case of lepra bacilli how a cluster can occur in this 

 situation (cf. section ' Leprosy,' p. 340) ; we can hardly consider that 

 there is a centrally directed lymph stream (Gruber, Leber). Perhaps 

 the fixed cells of the part may have a phagocytic action. 



Some recent researches are of especial interest regarding this point ; 

 Stock, 3 Homer, 3 A. Leber, Stargardt, 3 Morax, 4 have experimentally 

 produced a parenchymatous keratitis by infection with Trypanosoma, 



1 The lesions found in macerated or stillborn fetuses are not conclusive evidence with 

 regard to intra-vitam localization and distribution of an affection. Cf. cases by Schlimpert 

 (Leutschc JUed. Woch., 1906, p. 1942) and Bab (ibid., p. 1946). The conclusions which 

 these authors draw from their findings are not free from fallacies. 



' 2 A.f. 0., 1906, Ixii. 481. 



3 Ophth. Cong., Heidel., 1906. 4 Ann. d'Ocul., 1906, cxxxvi. 437. 



