IMPORTANT PATHOGENIC BACTERIA 129 



4. Special study. Demonstration of filament forma- 

 tion. 



a) Spread a loopful of a broth culture of B. anthracis 

 or B. subtilis on a cover glass. 



b) Dry and fix in the flame. 



c) Cover with strong acetic acid (80 per cent) for 

 5-10 seconds. 



d) Wash in water. 



e) Stain with gentian violet. 



/) Wash in water, dry, and mount in balsam. 



5. Special study. Inoculate a guinea-pig subcu- 

 taneously with o . 2 c.c. of a 24-hour-old broth culture of 

 B. anthracis, or insert a loopful of a 24-hour-old agar 

 culture in a "pocket" under the skin. When the 

 animal is dead, perform an autopsy, and observe the 

 hemorrhagic and gelatinous edema under the skin; also 

 the enlarged spleen and the hemorrhagic adrenals. 

 Make a stained preparation from the heart's blood, and 

 observe the lack of spores, and also the presence of 

 capsules and degenerate forms, which do not stain 

 well. Make a culture on agar from the heart's blood 

 or from the spleen and study the culture in the usual 

 manner. 



SECTION 9 



THE SPIRILLUM GROUP 



Members 



Spirillum of Finkler and Prior. 



Sp. metchnikovii. 



Sp. tyrogenum. 



And a number of spirilla indigenous to water. 



Inoculate agar slants from laboratory cultures of 

 Sp. of Finkler and Prior, and Sp. metchnikovii. The 

 spirillum of Asiatic cholera is studied in Section nB. 



