CLASSIFICATION OF BACTERIA 57 



without H 2 . The organisms are usually somewhat thermophilic. 

 As a rule micro-aerophilic; surface growth on media poor. 



Genus 7. Lactobacillus . Generic characters those of the tribe. 

 Type species, L. caucasicus (Kern?) Beijerinck. 



Tribe 6. Pasteur ellece. Gram-negative rods, showing bipolar 

 staining. Parasitic forms of slight fermentative power. 



Genus 8. Pasteurella. Aerobic and facultative. Powers of car- 

 bohydrate fermentation slight; no gas produced. Gelatin not 

 liquefied. Parasitic, frequently pathogenic, producing plague in 

 man and hemorrhagic septicemia in the lower animals. Type 

 species, P. cholerse-gallinarum (Fliigge) 1886 Trevisan. 



Tribe 7. Hemophilcece. Minute parasitic forms growing only in 

 presence of hemoglobin, ascitic fluid or other body fluids. 



Genus 9. Hemophilus. Minute rod-shaped cells, sometimes 

 thread forming and pleomorphic, non-motile, without spores, strict 

 parasites, growing best (or only) in presence of hemoglobin, and in 

 general requiring blood serum or ascitic fluid. Gram-negative. 

 Type species //. influenzas (Pfeiffer 1893). 



FAMILY VII. Bacillacece. Rods producing endospores, usually 

 Gram-positive. Flagella when present peritrichic. Often decom- 

 pose protein media actively through agency of enzymes. 



Genus 1. Bacillus. Aerobic forms. Mostly saprophytes. 

 Liquefy gelatin. Often occur in long threads and form rhizoid 

 colonies. Form of rod usually not greatly changed at sporulation. 

 Type species, B. subtilis Cohn. 



Genus 2. Clostridium. Anaerobes or micro-aerophiles. Often 

 parasitic. Rods frequently enlarged at sporulation, producing 

 clostridium or pleotridium forms. Type species, C. butyricum 

 Prazmowski. 



