474 BACTERIOLOGY. 



Do the same with anthrax spores, with spores of 

 bacillus subtilis and with the typhoid bacillus, and see 

 how the results compare. From these experiments what 

 will be the strength of corrosive sublimate necessary to 

 act as an antiseptic under these conditions for the organ- 

 isms employed ? 



Make a similar series of experiments, using a 5 per 

 cent, solution of carbolic acid. 



Determine the antiseptic point 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 different con- 

 ditions with and without the presence of albuminous 

 bodies other than the bacteria, and under varying condi- 

 tions of temperature. 



In making these experiments be careful to guard 

 against the introduction of enough sublimate into the 

 agar-agar from 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 which they may 

 be thoroughly 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 staphy loco ecus 

 pyogenes aureus, or anthrax spores, add 10 c.c. of cor- 

 rosive sublimate in 1 : 500 solution, and allow it to re- 

 main in contact with the organisms for only one-half the 

 time necessary to destroy them (use an organism for 



