332 MEDICAL BACTERIOLOGY 



sible danger from infection or distribution of bacilli and studied as 

 follows : 



a. Microscopical examinations of blood or of the spleen pulp of 

 animals show (when stained with Loeffler's methylen blue) large 

 bacteria in chains (5 or 6 segments) presenting the bamboo appear- 

 ance. 



~b. In hanging drop preparation large, homogeneous, immotile 

 bacilli. 



c. Agar plate cultures should also be made, and, from the separate 

 colonies, subcultures ; the gelatin stab being especially characteristic. 



d. In important cases (as in man) guinea pigs, or white mice, 

 should be inoculated, and, in case of death, organism isolated and 

 identified. 



Spirockaeta Obermeieri (relapsing fever). This organism is 

 found in the blood only during a paroxysm. It is a long slender 

 organism 6 or 7 times the diameter of a red blood corpuscle (45/*). 

 It has a brisk, vibratile movement in the direction of its long axis, 

 and is very sensitive to reagents of all kinds. Even the addition of 

 distilled water will cause it to disappear. Fresh blood is best, but 

 dried smears may be used and stained with f uchsin, or by Gunther 's 

 method : 



a. Dried films are treated with acetic acid (5%) 10 seconds, this 

 is removed by blowing and holding film over flask of strong ammonia 

 previously shaken. 



&. Stained in Ehrlich's gentian violet. 



c. Washed with water. 



d. Dried. 



e. Mounted in balsam or xylene. 

 /. Examined. 



Pus Micrococci. These are occasionally found, and for method 

 of detection see 105. 



Bacterium mallei. Sometimes found in the blood of those suffer- 

 ing with glanders. It may be detected in the blood- smears. For 

 special methods see 105. 



Bacterium pneumoniae (pneumococcus) . This germ is frequent- 

 ly present in fatal cases 24 to 48 hours before death. The blood 

 should be drawn with a sterile hypodermic syringe and about 1 cc. of 

 blood mixed with a tube of melted agar at 43 C. and poured into a 

 Petri dish. Characteristic colonies appear in 24 to 48 hours. 



