348 



A TEXTBOOK OF THEORETICAL BOTANY 



Fig. 338. — Treponema pulluiuiii. 'I'he causative agent 

 of syphilis. In liver of infected foetus. Silver 

 stained. 



committee was formed in 19 17 to reduce it to order. In 1925 they recom- 

 mended the following system, which has found wide acceptance, though it is 

 still subject to modification.* 



There are six Orders, containing the following principal Families :— 



1. Eubacteriales.— The " True " Bacteria. Simple rods or cocci. 



(i) Nitrobacteriaceae. Autotrophic Bacteria which carry out 

 chemosynthesis (p. 359), e.g., Nitrobacter, Azotobacter. 



(2) Pseudomonadaceae. Rods with polar flagella, e.g., Pseudo- 



monas. 



(3) Micrococcaceae. Spheroidal forms, not in chains, e.g., 



Stapliylococcus. 



(4) Spirillaceae. Spiral rods, e.g., Spinllum, Vibrio. 



{^) Lactobacteriaceae. Acid producers, e.g., Lactobacillus, 

 Streptococcus. 



(6) Parvobacteriaceae. Small parasitic rods, not active fer- 



menters, e.g., Pasteur ella, Haemophilus. 



(7) Enterobacteriaceae. Rods, mostly from the intestines. 



Active fermenters, e.g., Escherichia, Salmonella. 



(8) Bacillaceae. Spore forming rods. Bacillus, Clostridium. 



2. Actinomycetales. — The " Ray Fungi." Thin filamentous forms 



which show^ a tendency to branching. 



(i) Actinomycetaceae. Filaments long, branched and arranged 



in radial masses, e.g., Actinomyces. 

 (2) Mycobacteriaceae. Filaments short, occasionally branched, 



e.g., Corynebacterium, Mycobacterium tuherculose, the 



organism of tuberculosis. 



* Considerable changes in this classification were made in 1948, but it is still too early 

 to say whether they will be permanent. 



