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Exercise 35. Bacteriology of Anthrax or Splenic Fever 
MATERIALS: 
3 plain agar slopes 
1 plain broth 
1 9 cc. water blank 
Inoculated animal for post-mortem 
Sections showing organisms 
Slides 
Eosin-methylene blue stain for blood 
Culture of Bacillus anthracis 
The discoverer of the cause of tuberculosis, Robert Koch, set down four 
laws or rules for the study and proof that any specific organism causes a specific 
disease. These are known as Koch’s postulates and are: (1) The organism 
must be demonstrated in the circulation of tissues of the diseased animals; 
(2) organism must be isolated and cultivated in artificial media outside the 
body, and successive generations of a pure culture of that organism must be 
obtained: (3) such pure cultures must, when introduced into a healthy and 
susceptible animal, produce the specific disease; (4) the organism must be re¬ 
isolated from the blood or tissues of the inoculated animal. 
It is true that there are some diseases in which the specific organism cannot 
be cultivated outside of the animal body, or for which the causal organism 
has not been discovered. Examples of such diseases are hog cholera and 
rabies. Such diseases do not fulfill postulates (2) and (3), yet by the majority 
they are provisionally accepted as caused by a specific organism. Anthrax 
is chosen as a typical pathogenic organism that fulfills all of the postulates of 
Koch. 
Note. —Remember that the inoculating needles should be flamed im¬ 
mediately after they have been used. 
1. From the material supplied, inoculate an agar slope and a tube of broth. 
Label the tubes with the name of the organism and the desk number. 
2. Leave the tube from which you have inoculated your culture on the desk. 
Wipe off the desk with the HgCl 2 solution. Wash your hands with 1/1000 
HgCl 3 solution, then with soap and water. 
3. Draw and describe the cultures in broth and on the agar slope. Follow 
the outline in descriptions. See Appendix A. 
4. Make microscopic preparations from the agar slope and from the broth, 
staining with carbol fuchsin and Gram’s stain. The slides are to be labeled 
with the student’s name, name of the organism, and kind of medium from 
which the specimen was taken, and the kind of stain used. Remember 
that you are working with a dangerous organism and be especially 
careful not to scatter any of the organisms in making the slides. 
5. Draw and describe the preparations on each slide. See that the in¬ 
structor examines and checks each one. 
6. Observe the instructor inoculate a guinea pig with the same anthrax 
culture that has been used for study. 
7. Clean up the desks as before. 
