546 PATHOGENIC MICROORGANISMS 



or septum defects, cessation from smoking or other habits that 

 irritate the mucous membrane, and outdoor life, especially in the 

 sunlight, with sea baths if available. Specific antiseptic treatment 

 in general seems to us to have been a failure as far as the handling 

 of large numbers of men is concerned. 



The virulence of meningococci is a matter that is very difficult 

 to determine because of our inability to produce invasive infections 

 with regularity in any known laboratory animal. So far, extensive 

 attempts to determine the virulence of standardized injections into 

 mice have not succeeded. Death in most laboratory animals is due 

 to the toxic effects and not by invasion. This is a very unfortunate 

 circumstance, inasmuch as our failure to be able to distinguish 

 between virulent and non-virulent strains makes it impossible for 

 us to tell a dangerous carrier from one who is relatively harmless, 

 as we can in the case of diphtheria carriers. All we can do at the 

 present time is to regard as dangerous any. carrier whose meningo- 

 coccus agglutinates in a polyvalent serum. Those with strains which 

 neither agglutinate nor absorb with the polyvalent serum at our 

 disposal, if culturally they seem to be true meningococci, must be 

 regarded as suspicious. 



