522 BACTERIOLOGY. 



incubator after carefully labelling them. Note the order 

 in which growth appears. 



Do the same with anthrax spores, with spores of 

 bacillus subtilis, and with the typhoid bacillus, and com- 

 pare the results. From these experiments, what will be 

 the strength of corrosive sublimate necessary to anti- 

 sepsis under these conditions for the organisms em- 

 ployed ? 



Make a similar series of experiments using a 5 per 

 cent, solution of carbolic acid. 



Determine the antiseptic value of the common disin- 

 fectants for the organisms with which you are working. 



Determine the time necessary for the destruction of 

 the organisms with which you are working, by corro- 

 sive sublimate in 1 : 1000 solution, under diiferent con- 

 ditions — with and without the presence of albuminous 

 bodies other than the bacteria, and under varying con- 

 ditions of temperature. 



In making these experiments be careful to guard 

 against the introduction of sufficient sublimate into the 

 agar-agar with which the Petri plate is to be made to 

 inhibit the growth of the organisms which may not have 

 been destroyed by the sublimate. This may be done by 

 transferring two drops from the mixture of sublimate 

 and organism into not less than 10 c.c. of sterilized 

 physiological salt-solution, in M'hich they may be thor- 

 oughly shaken for from one to two minutes, or into the 

 solution of ammonium sulphide of the strength given. 



To 10 c.c. of a bouillon culture of staphylococcus 

 pyogenes aureus or anthrax spores add 10 c.c. of a 



