322 GENERAL MICROBIOLOGY 



An antiserum for each specific protein to be tested for 

 must be prepared by animal inoculation. Thus, if a test 

 for human blood is to be made, an anti-human-blood serum 

 must be used. 



Apparatus. Syringe and needles; sterile cow's blood; 

 sterile 500 c.c. Erlenmeyer flask containing glass beads; 

 rabbit; disinfectant; sterile flasks, tubes and pipettes; 

 sterile physiological salt solution. 



Method. 1. Inject a rabbit intra-abdominally with 

 6 c.c. sterile, defibrinated cow blood. On the sixth or seventh 

 day, repeat the injection, using 10 c.c. On the twelfth or 

 fourteenth day give 12 c.c. and again on the eighteenth or 

 twenty-first day give another 12 c.c. 



2. On the twenty-fourth or twenty-eighth day draw 

 a little blood from the rabbit and test it to determine its 

 property of precipitating cow blood. If it has a high litre, 

 the rabbit should be anesthetized and the bloo.d drawn from 

 the heart as explained in Exercises 1 and 7, pp. 295 and 309. 



3. Place the blood in a sterile container and allow to 

 clot. Draw the serum into small, sterile, glass bulbs hold- 

 ing 0.5 c.c. and seal the bulbs by heating the arm in a small 

 flame, using care to avoid heating the serum. Serum col- 

 lected in this way and placed in a cool, dark place will retain 

 its precipitating properties for several months. 



4. Dilute the blood to be tested with physiological salt- 

 solution. Several dilutions should be made, e.g., 1-200, 

 1-500, 1-1000, 1-10,000 and 2 c.c. of each dilution placed 

 in small test tubes. Place six to eight drops of the anti- 

 serum in each tube. If the suspect serum is from the same 

 species of animal as that used in immunizing the rabbit 

 (in this case, cow serum), immediate precipitation will 

 occur. After a few minutes' observation the tubes should 

 be incubated at 37 C. for twenty to thirty minutes and the 

 results noted. 



5. If the blood is dried, as a blood stain on cloth, the 

 quantity should be estimated and placed in a definite 



