902 EXPERIMENTAL INFECTION AND IMMUNITY 



EXPERIMENT 21. MECHANICAL ACTION OF BACTERIA 



1. Inject a 300-gram pig intraperitoneally with 2 c.c. of a forty-eight-hour-old 

 bouillon culture of Bacillus anthracis. Great care must be exercised in handling and 

 injecting this culture. 



2. Autopsy the animal at the end of forty-eight hours and make cultures on agar 

 slants of the heart's blood, liver, and spleen. Remove the heart, lungs, liver, spleen, 

 and kidneys, and place in 2 per cent, formalin. Prepare smears of the blood and 

 stain with Gram's method. 



3. After fixing for twenty-four hours, sections of these organs are to be prepared 

 and stained with methylene-blue and with Gram's stain. 



4. Examine the cultures at the end of twenty-four hours. 



5. Examine the sections. 



(a) Is the anthrax bacillus aggressive? 



(b) Does the anthrax bacillus produce much toxin? 



(c) Did the animal show any symptoms of its infection? 



(d) Are there evidences of peritonitis? 



(e) How do you explain the probable causes of death in human an- 

 thrax? 



EXERCISE 8. KINDS OF IMMUNITY 

 EXPERIMENT 22. PHAGOCYTOSIS IN NATURAL IMMUNITY 



1. Inject a healthy guinea-pig intraperitoneally with 1 c.c. of a twenty-four- 

 hour or forty-eight-hour glucose bouillon culture of streptococci of low or moderate 

 virulence. A culture of staphylococci may be used instead, although the former is 

 preferable. 



2. At the end of eighteen hours study the peritoneal fluid. Prepare smears and 

 stain with methylene-blue or other suitable stain. Prepare cultures in glucose 

 bouillon of the heart's blood. 



(a) Did the animal show any evidences of infection? 



(b) Has phagocytosis occurred in the peritoneal cavity? 



(c) What constituent of normal serum aids phagocytosis? 



(d) Did a bacteremia develop? 



EXPERIMENT 23. NATURAL ANTIBACTERIAL IMMUNITY 



1. Inject a 250-gram guinea-pig subcutaneously with 1 c.c. of a twenty-four-hour 

 bouillon culture of Bacillus anthracis. 



2. Inject a large albino rat with the same dose and in the same manner. 



3. Observe the animals for twenty-four to forty-eight hours. At autopsy pre- 

 pare smears and cultures of the heart blood of each. Stain the smears with methylene- 

 blue and according to the method of Gram. 



Do the animals present symptoms of infection? Are there any 

 differences between the two? 



