516 



BACTERIOLOGY. 



The contents of each of the capillary tubes are then in- 

 oculated into bouillon which is set aside at 37 to allow the 

 growth, if any, to develop. The contents are removed 

 as follows: The tube is first wiped dry and then one 



end is slig-htly scratched with 

 a file. The end is then removed 

 and .the opening- of the tube is 

 sterilized by touching' it 2 or 3 

 times to a flame. The tube is 

 held in a broad-pointed pair of 

 forceps, and, when cool, the cut 

 end is inserted into the culture 

 tube while the closed end is 

 slowly brought into contact with 

 a flame. The vapor thus pro- 

 duced promptly expels the liquid 

 from the capil- 

 lary. 



The student should 

 make suspensions 

 and test one or more 

 of the following- or- 

 ganisms, according- 

 to the directions 

 given above. Chol- 

 era vibrio, Typhoid 

 FIG. 75. Determination of the thermal death-point (F, G. N.)- bacillus, Anthrax 



bacillus (homogeneous 

 culture), Anthrax spores (p. 291) and Streptococcus pyog-enes. 



Action of moist heat at 58. The capillary tubes should be with- 

 drawn at the end of 5, 10, 15, 30 and 60 minutes' exposure. 



Action of moist heat at 70. The capillary tubes are withdrawn at 

 the end of 1, 3, 5 and 10 minutes. In addition to this the anthrax 

 spore tubes should be exposed for 15, 30 and 60 minutes. 



Action of moist heat at 100. ~ The capillary tubes are withdrawn at 

 the end of 1, 2 and 3 minutes. Additional anthrax spore tubes are ex- 

 posed for 5, 10 and 15 minutes. 



