BACTERIUM ANTHRACIS 569 



Do the anthrax threads, as seen in a fresh, growing, 

 hanging drop, present the same morphological appearance 

 as when dried and stained upon a cover-slip? How do they 

 differ? 



Liquefy a tube of agar-agar, and when it is at the tem- 

 perature of 40° to 43° C. add a very minute quantity of an 

 anthrax culture which is far advanced in the spore-stage. 

 Mix it thoroughly with the liquid agar-agar and from this 

 prepare several hanging drops under strict antiseptic pre- 

 cautions, using the fluid agar-agar for the drops instead 

 of bouillon or salt-solution. Select from among these 

 preparations that one in which the smallest number of 

 spores are present. Under the microscope observe the 

 development of a spore into a mature cell. Describe care- 

 fully the developmental stages. 



Prepare a 1 : 1000 solution of carbolic acid in bouillon. 

 Inoculate this with virulent anthrax spores. If no develop- 

 ment occurs after two or three days at the temperature of 

 the thermostat, prepare a solution of 1 : 1200, and continue 

 until the point is reached at which the amount of carbolic 

 acid present just permits of the development of the spores. 

 When the proper dilution is reached prepare a dozen of 

 such tubes and inoculate one of them with virulent anthrax 

 spores. As soon as development is well advanced transfer 

 a loopful from this tube into a second of the carbolic acid 

 tubes; when this has developed, then from this into a third, 

 etc. After five or six generations have been treated in this 

 way study the spore-production of the organisms in that 

 tube. If it is normal, continue to inoculate from one car- 

 bolic acid tube to another, and see if it is possible by this 



