224 METHODS OF CULTIVATION 



forms a cylindrical mass in the lower portion of the 

 tube and presents an upper surface which is at right 

 angles to the long axis of the tube. 



This is employed for "stab" or "stick" cultivations 

 (Stichcultur) , or by inoculating the medium whilst 

 fluid, and allowing to solidify in this position, for 

 "shake" cultivations. 



Streak Culture. 



1. Flame the plugs, sterilise the platinum loop (or 

 spatula). Open the tubes and charge the loop as in 

 previous inoculation. 



2. Pass the infected loop to the bottom of the tube 

 to be inoculated and draw it, as lightly as possible, 

 along the centre of the surface of the medium, ter- 

 minating the "streak" over the thin layer of medium 

 near the mouth of the tube. 



3. Replug the tubes, sterilise the platinum loop. 



4. Label the newly inoculated tube and incubate. 



Smear Culture. Proceed generally as in streak cul- 

 ture, but rub the infected loop all over the surface of 

 the medium, instead of restricting the inoculation to 

 a narrow line. 



NOTE. Gelatine and agar oblique tubes should be freshly 

 "slanted" before use. 



Stab Culture. 



1. Flame the plugs, open the tubes, sterilise the 

 platinum needle and charge it with the inoculum as 

 in the previous cultivations. 



2. Pass the platinum needle into the tube to be 

 inoculated until it touches the centre of the surface of 

 the medium. Now thrust it deeply into the sub- 

 stance of the medium, keeping the needle as nearly as 

 possible in the axis of the cylinder of medium. Then 

 withdraw the needle. 



3. Replug the tubes. Sterilise the platinum needle. 



