178 TECHNOLOGY OF BACTERIA. 



preparing a considerable number of these flasks at 

 one time, and leaving them, in a suitable vessel 

 filled with water, for twenty-four hours or longer 

 upon the kitchen stove. Here the water-bath is 

 kept boiling at intervals, and the contents of the 

 flasks can scarcely fail of being subjected to a tem- 

 perature of 212 Fahr. for eight or ten hours. 

 When the time is less than this, failures in sterili- 

 zation are likely to occur, and it is always best to 

 keep on the safe side. The flasks are next placed 

 in a culture-oven for two or three days, at a tem- 

 perature of 35 to 38 (95 to 100 Fahr.), to $ test 

 the success of the previous operation, steriliza- 

 tion. If at the end of this time the contents re- 

 main transparent, and no film mycodcrma has 

 formed upon the surface of the liquid, the flasks 

 may be put aside for future use, and can be pre- 

 served indefinitely. 



" To inoculate the liquid contained in one of 

 these little flasks with organisms from any source, 

 the end of the tube is first heated, to destroy germs 

 attached to the exterior ; the extremity is then 

 broken off with sterilized by heat forceps ; 

 the bulb is very gently heated so as to force out 

 a little air ; and the open extremity is plunged 

 into the liquid containing the organism to be cul- 

 tivated. The smallest quantity of this is suffi- 

 cient, and as soon as the inoculation is effected, 

 the end of the tube is again sealed in the flame 

 of an alcohol lamp. A little experience will en- 

 able the operator to inoculate one tube from an- 



