80 



Heiuorrliai 



Septicfc 



or cii'tcr sul)st.'(jiu'iit wasliing in alcoliol or Vii to 1% acetic acid. On the 

 otlier liand, it is tlifficiilt to obtain the polar stain in ])aeilli originating 

 from artificial cultures. 



Cultivation. Tlie bacilli are easily isolated from 

 cases of an acute septicemic character, while from 

 chronic cases this is more difficult and sometimes im- 

 l)0ssibk'. The recjuirements of artificial cultivation are : 

 temperature of 13-28^ C. and alkaline or at least neutral 

 reaction of the medium. In vacuum the bacteria grow 

 only when the medium is inoculated with numerous 

 organisms, and then only for a short time. 



A frequent characteristic of the 

 cultures is their viscosity (this is also 

 striking in the peritoneal exudate of 

 inoculated guinea pigs), probably due 

 to the sticky capsule which covers the 

 bacteria. 



The colonies formed on gelatin are 

 no larger than a millet seed. They are 

 at first transparent, often resembling 

 a dew-drop, and frequently iridescent. 

 Later they are whitish, of a hyaline- 

 cartilage-like appearance. In the depth 

 of the medium the punctiform colonies 

 unite along the stab and form a con- 

 tinuous white streak (Fig. 25). Sim- 

 ilar colonies develop on the surface of 

 the agar cultures, but do not extend 

 to the wall of the test tube (B'ig. 26) ; 

 cultures several days old are viscid : 

 when still older they adhere firmly to 

 the medium On coagulated blood 

 serum a very fine membrane forms 

 which is at first transparent and later 

 whitish. Bouillon M'ith the addition of 

 peptone or blood serum usually be- 

 comes more or less uniformly cloudy; 

 in some of the varieties, however, the 

 fluid clears, sometimes first forming a 

 slimy and later a fine granular sedi- 

 ment ; occasionally also a delicate, 

 whitish membrane develops on the sur- 

 face The addition of sugar or glycerin does not promote, but rather 

 retards the growth. Dextrose bouillon is not fermented. No growth 

 takes place on potatoes Avith a natural acid reaction ; when artificially 

 alkalinized a grayish-yellow deposit forms. 



Fiji. 25. (iela- 

 tin stai) culture 

 oft lie lincillushi- 

 puUiris scpticus. 



V\g. 26. Agar 

 stab culture of 

 the hucUlufs hi- 

 polaris septicus. 



Aiiunals inoculated witli a certain variety jirodiiee a serum which will have 

 the highest agglutination for that particular variety (up to 1:60,000), hut it will 

 also agglutinate to a lesser degree other varieties (1:1000-6000). Sometimes, how- 

 ever, some of the varieties are in no way influenced. Therefore the agglutination 

 cannot be utilized for the identification or separation of the different varieties 

 (Chamberland «& Jouan). 



