164 TEXT-BOOK OF BACTERIOLOGY. 



that rabbits can outlive an inoculation with anthrax if they are 

 afterward treated with prodigiosus. In the one case the excretions 

 of two different micro-organisms unite in common action; in the 

 other they counteract each other and become harmless. 



Bacillus Indicus. 



A kind of bacterium wmch has many points of resemblance in 

 common with the Micrococcus prodigiosus, which is, therefore, usu- 

 ally described immediately after it, is the Bacillus indicus. It de- 

 rives its name from its having been found by Koch in the intestines 

 of an Indian monkey when he was in India seeking the cause of 

 cholera. He thought it worthy, on account of its striking peculiari- 

 ties, to be introduced into the cultures of our laboratories. 



The Bacillus indicus is small, slender, extremely lively in its 

 movements, and has slightly-rounded corners. The presence of 

 spores has not yet been clearly established, yet the indicus, like the 

 prodigiosus, has the faculty of resisting for a long time various 

 deleterious influences — especially that of desiccation — without hav- 

 ing any recognizable permanent forms. 



For instance, a small quantity of potato culture grown in India 

 was laid between blotting-paper, and in this state sent to Germany 

 in a letter. This letter on its way was subjected to all the measures 

 employed by the sanitary police of the different countries through 

 which it passed for disinfecting the mails coming from cholera dis- 

 tricts. It was perforated and fumigated with chlorine and sulphur, 

 according to the postal regulations, but the first experiments made 

 at the Imperial Health Office in Berlin at once showed that the 

 vitality of the bacteria had suffered no harm whatever from all 

 these operations. 



As might be expected from its origin and its character as a 

 parasitic bacterium, the indicus thrives without difficulty at body 

 temperature; j'et it is also able to grow at lower temperature, and 

 even develops some of its peculiarities better outside the incubator. 



It is an optional anaerobe, capable of living without air, but 

 thrives more luxuriantly when it has access to the atmosphere. 



It takes the anilin stains readily. 



On the gelatin plate it is distinguished, like the prodigiosus, by 

 a remarkablj' rapid growth and a very vigorous liquefaction of 

 the culture medium. In order to get isolated colonies suitable for 

 close investigation, we must prepare four or even five different 

 plates. On the last dilution small white specks below the surface, 

 can be seen with the naked eye, while the surface colonies show 



