452 BACTERIOLOGY. 



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 exactly 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 twen- 

 ty-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 place in the incubator. Note the results. 

 Do they correspond with those obtained in the preceding 

 experiment ? 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. 



