20 A MANUAL OF BACTERIOLOGY 



B. ORDER THIOBACTEEIALES. 



Cells free or united into filaments, containing granules of 

 sulphur or of bacterio-purpurin or both. Water forms. (The 

 " sulphur " bacteria.) 



C. ORDER CHLAMYDOBACTERIALES. 

 Cells united into filaments, often with false branching, and 

 usually a well-marked sheath. Iron often present. Water forms. 

 The "iron " bacteria.) 



D. ORDER ACTINOMYCETALES. 



Non-motile cells, usually elongated, frequently filamentous. 

 Tendency to branching, in some a definite branched mycelium. 

 Endospores not formed, but conidia sometimes present. Usually 

 Gram-positive and aerobic. Some species parasitic. 



Family I. ACTINOMYCETACEAE. Filamentous forms often 

 branched and mycelial. Conidia sometimes present. 



Genus 1. ACTINOBACILLUS. Resemble streptobacilli. In 

 lesions mycelium not formed, but finger-shaped branched 

 cells at periphery. Gram-negative and not acid-fast. 



Genus 2. LEPTOTRICHIA. Thick threads, unbranched, fre- 

 quently clubbed. No conidia. Gram-positive when young. 

 Parasitic. 



Genus 3. ACTINOMYCES. Form a much branched mycelium. 

 May break up into segments which function as conidia. 

 Sometimes parasitic with clubbed ends to filaments in the 

 tissues. 



Genus 4. ERYSIPELOTHRIX. Rod-shaped organisms with ten- 

 dency to long filament formation which may branch. No 

 spores. Non-motile. Gram-positive and usually parasitic. 

 (Swine erysipelas.) 



Family II. MYCOBACTERIACEAE. Parasitic forms. Rod-shaped, 

 frequently irregular, rarely filamentous or branching. No 

 conidia. 



Genus 1. MYCOBACTERIUM. Slender rods, often clubbed, occa- 

 sionally branched. Non-motile, no endospores. Acid-fast 

 and Gram -positive. (Tubercle bacillus.) 



Genus 2. CORYNEBACTERIUM. Slender rods, often clubbed, 

 occasionally branched. Non-motile, no endospores. Gram- 



