Proteus Vulgaris, Hauser. 



Origin. — It is very widely distributed and is commonly 

 present in the putrefaction of animal proteins (p. 111). It 

 has also been met with in water, in meconium, in purulent 

 abscesses, and in the blood and tissues of several cases of 

 fatal putrid infection of the intestines. 



Form. — Rods, of varying length, from short oval forms 

 to those which are 2 to 6 times as long as wide. It is usu- 

 ally bent and grows in pairs; may also form twisted, inter- 

 woven threads. Eoundish involution forms are common. 



Motility. — It is actively motile. . Flagella are very 

 numerous (60-100), and are arranged all over the surface. 



Sporulation. — Not observed, though cultures are re- 

 sistant to desiccation and retain vitality for many months. 



Anilin dyes. — It stains readily; not by Gram's method. 



Growth.— Very rapid. 



Gelatin plates.— Ha-TpiA a.nA extensive liquefaction of the gelatin. 

 The colonies are yellowish brown, with bristly borders, and in soft gel- 

 atin tend to spread over the surface and assume peculiar figures. De- 

 tached portions of colonies can be seen to move about — "swarming 

 islets." A disagreeable odor and an alkaline reaction is present. 



Stab cuZiure.— Rapid liquefaction along entire line of inoculation, 

 so that in a few days the entire contents are liquefied. The fluid is at 

 first diffusely cloudy, but later clears up and a flocculent sediment 

 settles on the bottom, while on the top a grayish white layer is formed. 



Streak culture.— On agar, it forms a grayish, slimy, rapidly spread- 

 ing growth. On potato, it forms a dirty colored, sticky covering. 



Oxygen requirements. — It is a facultative anaerobe. 



Temperature. — The optimum lies between 20 and 24°. 

 It grows excellently in the incubator. 



Behavior to gelatin. — This is rapidly liquefied. 



Aerogenesis. — It forms hydrogen sulphide. 



Pathogenesis. — Small doses have no efEect. The injec- 

 tion of large quantities of living, or filtered cultures pro- 

 duces in rabbits and guinea-pigs toxic effects, and death 

 may even result. It is therefore toxicogenic. At times, it 

 may even take on a pathogenic character. 



This and several related species are included in the 



Bacterium termo of the older writers. 



220 



