348 



EXPERIMENTAL INOCULATION OF ANIMALS 



tion completed according to the requirements of the 

 particular case. 



This method is quite satisfactory when the injection 

 is made into the pleural or abdominal cavities or directly 

 into a vein but if the injection has to be made into the 

 subcutaneous tissue the "fall" may not be sufficient to 

 force the fluid in. In this case it will be necessary to 

 transfer the culture to a sterile wash-bottle and fasten a 

 rubber hand bellows to the air inlet tube (interposing an 

 air filter) and attach the tubing with the injection 

 needle to the outlet tube (Fig. 174). By careful use 

 sufficient force can be obtained to drive the injec- 

 tion in. 



(b) Cultivations on Solid Media (e. g., Sloped Agar) . 

 i. By means of a sterile graduated pipette introduce 



FIG. 174. Arrangement of pressure injection apparatus. 



a suitable small quantity of sterile bouillon (or sterile 

 normal saline solution) into the culture tube. 



2. With a sterile platinum loop or spatula scrape 

 the bacterial growth off the surface of the medium, 

 and emulsify it with the bouillon. It then becomes 

 to all intents and purposes a fluid inoculum. 



3. Pour the emulsion into a sterile capsule and fill 

 the syringe therefrom. 



