SOLID MEDIA 



223 



the tubes as nearly horizontal as is possible without 

 allowing the fluid in the bouillon tube to reach the 

 cotton-wool plug (Fig. 117). 



3. Sterilise the platinum loop and allow it to cool. 1 



4. Grasp the plug of the tube containing the culti- 

 vation between the little finger and palm of the hand 

 and remove it from the tube. 



5. Grasp the plug of the bouillon tube between the 

 fourth finger and the ball of the thumb and remove it 

 from the tube. 



6. Pass the platinum loop into the tube containing 

 the culture do not allow the loop to touch the sides 

 of the tube, or the handle to touch the medium and 

 remove a small portion of the growth; withdraw the 

 loop from the tube, keeping the infected side of the 

 loop downward. 



7. Pass the loop into the bouillon. tube almost down 

 to the level of the fluid, reverse the loop so that the 

 infected side faces upward, emulsify the portion of 

 the growth in the moisture adhering to the side of the 

 tube which is uppermost. Withdraw the loop. 



8. Replug both tubes. 



9. Sterilise the platinum loop. 



10. Label the bouillon tube with (a) the name of 

 the organism and (b) the date of inoculation. 



11. Incubate. 



2. Solid Media. Solid media are stored in tubes in 

 one of two ways : 



1. Obb'que tube or slanted tube (Fig. 118), in which 

 the medium has been allowed to solidify whilst the tube 

 was retained in an inclined position, so forming an 

 extensive surface of medium extending from the bot- 

 tom of the tube almost to its mouth. 



This is employed for " streak" or "smear" cultiva- 

 tions (Strichcultur) . 



2. Straight tube (Fig. 119), in which the medium 



1 See also method of opening and closing culture tubes, pages 74-76. 



