424 SA OTEBIOL OGY. 



Prepare a 1 : 1000 solution of carbolic acid ia bouil- 

 lon. Inoculate this with virulent anthrax spores. If 

 no development 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 jMsi 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 carbolic acid tube to another, and 

 see if it is possible by this means to influence in any 

 way the production of spores by the organism with 

 which you are working. What is the effect, if any ? 



Prepare two bouillon cultures, each from one drop of 

 blood of an animal dead of anthrax. (Why from the 

 blood of an animal and not from a culture ?) Allow one 

 of them to grow for from fourteen to eighteen hours in 

 the incubator; allow the other to grow at the same tem- 

 perature for three or four days. Remove the first after 

 the time mentioned and subject it to a temperature of 

 80° C. for thirty minutes. At the end of this time 

 prepare four plates from it. Make each plate with one 

 drop from the heated bouillon culture. At the end of 

 three or four days treat the second tube in identically 

 the same way. How do the number of colonies which 

 develop from the two different cultures compare ? Was 



