CLASSIFICATION OF BACTERIA 37 



Cobb's disease of sugar cane. Ps. pyocyanea causes blue pus. Ps. 

 putida occurs in water, where it develops a green fluorescent pigment. 

 Ps. syncyanea produces in milk a blue coloring matter (blue milk). 

 Ps. etiropcea belongs to the group of organisms which cause nitrification. 



Family 3. Spirillace^.^ — Spirally wound or bent cells with occa- 

 sional endospore formation, usually motile. Cell division transverse 

 to the long axis of the cell. 



Spirosoma. — -Spirally bent, rigid cells usually rather large and with- 

 out flagella. Unicellular free or enveloped in a gelatinous capsule. 

 Only a few species are known. 



Microspira. — -Comma-shaped, or sausage-shaped, single, or united 

 cells, motile by means of a single, wavy, polar flagellum (rarely two or 

 three flagella), rarely longer tha*n the cell. Endospores unknown. 

 Usually united with the next genus. 



Spirillum. — Rigid rod-shaped cells of varying thicknesses, lengths 

 and pitch of spiral turns, hence, either as long screws, or loosely wound. 

 Flagella occur at one or both ends of the cells as polar tufts varying in 

 number from five to twenty. In some species, endospore formation 

 has been observed. Sp. comma is the cause of asiatic cholera and is 

 found in cultures often in long spirally wound filaments. There are 

 nmny non-pathogenic spirilla in water from rivers and ponds as S. 

 danubicum in the Danube, Sp. berolinense in Spree water, Sp. ruftim 

 in stagnant water. Sp. rufum forms blood-red slimy masses between 

 decaying algae. 



SpirochcBta. — Thin, flexible, snake-like, motile cells usually quite 

 long without observed flagella and endospores, and unsegmented. 

 Spirochceta Obermeieri is the cause of relapsing fever (f ebris recurrans) . 

 S. {Treponema) pallida is the organism of syphilis. S. dentium is found 

 associated with the teeth in man. 



Family 4. Phycobacteriace^ (Chlamydobacteriace^). — Cylin- 

 dric cells united into sheath-surrounded threads and reproducing by 

 motile or non-motile conidia, which arise from the vegetative cells 

 without a resting stage. 



Streptothrix (== Chlamydothrix, Leptothrix, Gallionella). — Non-motile 

 cylindric cells in unbranched threads possessing a sheath of varying 

 thickness. Septa vague. Reproduction is accomplished by roundish, 

 non-motile conidia arising from the vegetative cells. S. fluitans in 

 water. 



