100 



MICROBIOLOGY 



facing upward', and grasp them about the middle of the 

 upper half. Sterilize the platinum loop by passing it through 

 the gas name, care being taken that the handle is also named 

 for a distance of at least 15 cm. Then carefully remove the 

 plugs from the tubes and hold them between the fingers in 

 such a manner that the tube ends, projecting outward, will 

 not touch anything during the inoculating process. Insert 

 the wire loop carefully into the culture arid transfer a loop- 



ful of the culture to the 

 tube of bouillon and 

 gently rinse. The loop 

 is then withdrawn, the 

 plugs replaced in their 

 respective tubes, and the 

 loop flamed and put 

 aside. Label the fresh- 

 ly inoculated tube with 

 the name of the organ- 

 ism, source, and date. 



In inoculating tubes 

 of bouillon from a col- 

 ony, a platinum wire 

 with the end slightly 



bent is preferable to a loop. In inoculating bouillon from 

 tissues, a platinum spatula is heated in a gas flame to a red 

 heat and the surface of the organ is scorched. With a pair 

 of flamed (sterile) fine forceps an opening through the 

 scorched surface is made and a bit of tissue underneath is 

 crushed. With the platinum loop take up a loopful of the 

 crushed tissue. 



Inoculating tubes of agar and gelatin. Ordinarily the 

 agar is inclined or slanted in the tube before it is inoculated. 

 In this case it is spoken of as inclined or slant agar. Occa- 

 sionally the agar is inoculated without inclining it. Cultures 

 made in this manner are spoken of as "stab" or "stick" 

 cultures, (a) Inclined or slant agar. Stand tubes of agar in 

 a wire basket in a water bath and boil it until the agar is 



Fig. 34. A convenient block for 

 holding test tubes. 



