100 BACTERIOLOGY OF THE EYE 



latest work of A. Leber 1 with typhoid and cholera show that the amount of 

 protective bodies in the anterior chamber, which though still perceptible, is 

 normally very low, is considerably raised by any irritation. 



It is remarkable that it was higher in the case of passive than in the case 

 of active immunity, although the serum is richer in protective substances in the 

 latter than in the former. These are, perhaps, retained more in the blood in active 

 immunity. The aqueous of the immunized animal showed only a very feeble 

 bacteriolytic action. Schneider (Miincli. Med. Woch., 1907, p. 146) reports the 

 complete absence of alexin (hsemolj'sin, bacteriolytic or bacteriotropic substance) 

 in the normal aqueous of an immunized animal. These bodies were only found 

 after tapping. 



E. Possek 2 has carried out further researches into the cytotoxin contents of the 

 vitreous in normal and immunized subjects. Although diffusible substances slowly 

 pass into it from the blood, this does not occur with antibodies. The normal vitreous 

 is wanting in the antibacterial power possessed by the blood-serum ; and, further, 

 it has no hsemolytic power, such as the serum of the pig, for example, has on 

 bullock's blood. Neither does the vitreous participate in any artificially produced 

 increase in haemolytic power of the serum. Possek's results confirm the principle 

 laid down by Homer 3 of ' the retention of cytotoxins by the secretory apparatus of 

 the eye.' It was only after repeated saline injections and tappings of the anterior 

 chamber that traces of hsemolysin could be found in the vitreous, as was shown by 

 Wessely, 4 although such substance could readily be found in the anterior chamber 

 after slight irritation. Investigating the occurrence of bactericidal substances in the 

 eyes of a series of non-immunized individuals, and working with the bacilli 

 of dysentery, Zur Nedden 5 found the normal aqueous and vitreous not to be 

 bactericidal, but merely bad media for growth. Bactericidal material, however, 

 entered the anterior chamber after puncture, and similarly but more slowly, after 

 loss of vitreous into that chamber. Congestion of the eye or head by Bier's method 

 produced no bactericidal increase, though an inflammatory condition of the 

 globe did. 



If we assume that a similar condition obtains in the human subject, 

 then prophylactic pneumococcal immunity after cataract operation 

 may have a certain value, as the opening of the eye and the whole 

 procedure causes a flow from the vessels, both into the interior and 

 also outwards, with which there may be some access of protective sub- 

 stances. Should any inflammation occur, the reactionary exudation 

 from the vessels and our serum treatment will have still more influ- 

 ence in this direction. The cornea, too, according to Eomer, partici- 

 pates to a high degree in the immunity. Serum treatment, therefore, 

 can be of value. We cannot, however, affirm that its restraining action 

 is at all equivalent to the influence which the opening of the lens 

 capsule has in favouring an infection. 



1 ' Immunitatsverhiiltnisse der vorderen Augenkaramer,' A. f. 0., 1906, Ixiv. 413 (see 

 here collected literature). 



2 K. M.f. A., 1906, Bd. ii. 



'* A.f. 0., 1905, lx., 'Die Cataracta senilis voni Standpunkt der Serumforscliung. ' 



4 Dewtsch. Med. Woch., 1902, and ' Flussigkeitswechsel im menschl. Auge ' in ' Ergebnisse 

 der Physiologic,' 1905. 



5 A.f. 0., 1907, Ixv., S. 267. 



