378 EXPERIMENTAL INFECTIONS DURING LIFE 



1. Sterilise an all-glass syringe of suitable size, and 

 when cool draw into the syringe some sterile sodium 

 citrate solution and moisten the whole of the interior of 

 the barrel ; then eject all the citrate solution if less than 

 5 c.c. blood are to be withdrawn ; if more than 5 c.c. are 

 required retain about half a cubic centimetre of the fluid 

 in the syringe. This prevents coagulation of the blood. 



The sodium citrate solution is prepared by dissolving : 



Sodium citrate 10 gramme. 



Sodium chloride -75 grammes. 



In distilled water 100 c.c. 



Sterilise by boiling. 



2. Prepare the animal as for intravenous inoculation 

 (see page 363) and introduce the syringe needle into the 

 lumen of the selected vein. 



3. Slowly withdraw the piston of the syringe. When 

 sufficient blood has been collected direct the assistant 

 to release the proximal compression of the vein; and 

 withdraw the needle. 



4. Remove the needle from the nozzle of the syringe 

 and deliver the citrated blood into a small Ehlenmeyer 

 flask containing about 250 c.c. of nutrient broth. 



5. Label, incubate and examine daily until growth 

 occurs or until the expiration of ten days. 



c. The serological examination of the blood is directed 

 to the demonstration of the presence of certain specific 

 antibodies in the sera of experimentally infected an- 

 imals, and within certain limits to an estimation of 

 their amounts. 



The chief of these bodies are : 



Antitoxin. 



Agglutinin. 



Precipitin. 



Opsonin. 



Immune body or Bacteriolysin. 



None of these substances are capable of isolation in 



