EXPERIMENTS. 473 



Into each of two tubes containing 10 c.c. the one of 

 normal salt solution, the other of bouillon add as much 

 of a spore-containing culture of anthrax bacilli as can 

 be held upon the loop of the platinum wire. Mix this 

 thoroughly so that no clumps exist, and then add ex- 

 actly 10 c.c. of a 1:500 solution of corrosive sublimate. 

 Mix thoroughly and at the end of five minutes transfer 

 a drop from each tube into a tube of liquefied agar-agar. 

 Pour this immediately into a Petri dish. Label each 

 dish carefully and place them in the incubator. Note 

 the results at the end of twenty-four, forty-eight, and 

 seventy-two hours. How do you explain them ? 



Make identically the same experiment with the same 

 spore-containing culture of anthrax bacilli, except that 

 the drop from the mixture is to be transferred to 10 c.c. 

 of a mixture of equal parts of ammonium sulphide and 

 sterilized distilled water. After remaining in this for 

 about half a minute, a drop is to be transferred to a tube 

 of liquefied agar-agar, poured into Petri dishes, labelled, 

 and placed in the incubator. Note the results. Do they 

 correspond with those obtained in the preceding experi- 

 ment ? How are the differences explained ? 



Prepare a 1: 1000 solution of corrosive sublimate. To 

 each of twelve tubes containing exactly 10 c.c. of bouillon 

 add one drop to the first, two drops to the second, and 

 so on until the last tube has had twelve drops added to 

 it. Mix thoroughly and then inoculate each with one 

 wire-loopful of a bouillon culture of staphylococcus 

 pyogenes aureus. Place them all in the incubator after 

 carefully labelling them. Note the order in which 

 growth appears. 



