SERIAL CULTIVATIONS 251 



2. Collect a few drops of human blood, under all 

 aseptic conditions, in a sterile capillary teat pipette. 



3. Raise the cover of the Petri dish very slightly, 

 insert the extremity of the capillary pipette, and deposit 

 the blood on the centre of the agar surface. Close the 

 dish. 



4. Charge a platinum loop with a small quantity of 

 the inoculum. Raise the cover of the plate, introduce 

 the loop, mix its contents with the drop of blood, 

 remove the loop, close the dish and sterilise the loop. 



5. Finally smear the mixture over the surface of the 

 agar with a sterilised L-shaped rod. 



6. Label and incubate. 



(If considered necessary, two, three, or more similar 

 plates may be inoculated in series.) 



(/) Blood Agar, Animal. 



When preparing citrated blood agar (page 171) it is 

 always advisable to pour several blood agar tubes into 

 plates, which can be stored in the ice chest ready for 

 use at any moment for surface plate cultures. 



(g) Hanging-drop or block culture, (vide page 233). 



3. Serial Cultivations. These are usually made upon 

 agar or blood-serum, although gelatine may also be used. 

 The method is as follows : 



1. Take at least four " slanted" tubes of media and 

 number them consecutively. 



2. Flame all the plugs and see that each can be 

 readily removed. 



3. Charge the platinum loop with a small quantity 

 of the inoculum, observing the usual routine, and plant 

 tube No. i, smearing thoroughly all over the surface. 

 If any water of condensation has collected at the 

 bottom of the tube, use this as a diluent before 

 smearing the contents of the loop over the surface of 

 the medium. 



4. Without sterilising or recharging the loop, inocu- 



