254 ORDER I. PSEUDOMONADALES 



Cells form either long screws or portions of a turn. Volutin granules are usually present. 

 Usually motile by means of a tuft of polar flagella (5 to 20) which may occur at one or both 

 ends of the cells. Aerobic, growing well on ordinary culture media except for one saprophyte 

 and the pathogenic species; these have not yet been cultivated. Usually found in fresh and 

 salt water containing organic matter. 



The type species is Spirillum undula (Miiller) Ehrenberg. 



Key to the species of genus Spirillum. 



I. One micron or less in diameter. 



A. Volutin granules present. 



1. Slow to rapid liquefaction of gelatin. 



a. Grajash to brown growth on potato. 



1. Spirilluni undula. 

 aa. Light yellowi.sh orange growth on potato. 



2. Spirillum serpens. 



2. No liquefaction of gelatin. Of small size (0.5 micron in diameter). 



a. Colonies on agar white becoming brownish black and slightly wrinkled. 



3. Spirillum itersonii. 

 aa. Colonies on agar white and smooth. 



4. Spirillum tenue. 



B. No volutin granules observed. 



1. Single fiagellum. From sea water. 



5. Spirillum virginianum. 



2. Tuft of flagella. From blood of rats and mice. 



6. Spirillum minus. 

 II. Over 1 micron in diameter. 



A. Grow poorly or not at all on peptone agar media. 



1. Grows poorly on peptone agar and potato. 



7. Spirillum kutscheri. 



2. Has not been cultivated on artificial media. Very evident volutin granules. 



8. Spirillum volutans. 



B. Grows abundantly on peptone media. Cells may be deformed with fat droplets. 



9. Spirillum lipoferum. 



1. Spirillum undula (Miiller, 1786) Agar colonies: Grayish white, smooth. 



Ehrenberg, 1832. {Vibrio undula Miiller, Broth: Turbid. 



Animalcula infusoria et marina, 1786; Potato: Grayish brown growth. 



Ehrenberg, Physik. Abhandlungen d. k. Indole not produced. 



Berl. Akad., 1832, 38.) Catala.se-positive. 



un'du.la. L. noun unda a wave; M.L. Nitrites not produced from nitrates, 



dim.fem.n. undula a small wave. Aerobic, facultative. 



Stout threads, 0.9 micron in diameter, Optimum temperature, 25° C. 



with one-half to three turns. The wave Cohn (Beitrage z. Biol. d. Pflanzen, 1, 



lengths are 6 microns. Width of spiral, 3.0 Heft 2, 1875, 132) reports that he could not 



microns. Tufts of three to nine flagella at distinguish this organism from Vibrio 



each pole. Volutin granules present. Gram- prolifer Ehrenberg. 



negative. Habitat: Putrid and stagnant water. 



Gelatin colonies: The surface colonies are 



circular, granular, greenish yellow, entire. 2. Spirillum serpens (Miiller, 1786) 



Gelatin stab: Thick, white, rugose sur- Winter, 1884. {Vibrio serpens Miiller, Ani- 



face growth. Very slow liquefaction. malcula infusoria et marina, 1786, 43; 



