VACCINE-THERAPY 



21 



on the surface of the medium, and draw it slowly along 

 the whole length, care being taken not to graze the surface 

 with the loop end. Withdraw the needle and sterilize it as 

 before. Now take up the cotton-wool with forceps and set 

 it on fire, and whilst aflame thrust it into the mouth of 

 the tube ; label the tube with grease pencil — owner's 

 name, animal, and date — and put into the incubator. 



Where we desire a stab culture, the process adopted is 



s&=^ 



Fig. 11. — Plugged Stab Medium Tube. 



the same ; but in this case we pass the needle, not looped, 

 but pointed, laden with the pus or other material, through 

 the axis of the medium, give it a slight rotation, withdraw, 

 and plug as before. 



Plate Cultivation. 



Glass plates were originally used for cultivation, but 

 shallow dishes 2 or 3 inches in diameter, with lids, and 

 known as Petri dishes, are now in use. 



