NON-PATHOGENIC SPIRILLA. 



695 



Morphology. Long, flexible, spiral filaments. The spiral curves are 

 close and regular, but the extremely long filaments present secondary, wave- 

 like curves which are not uniform. The ends of the filaments are blunt. 

 They may attain a length of one hundred to two hundred jn ; the movements 

 are extremely active. 



Biological Characters not determined. 



414. VIBRIO RUGULA (Mliller). 



Found in swamp water, in faeces, and in tartar from the teeth. 



Morphology. Kod-shaped cells from 6 to 8 /* long and from 0.5 to 2.5 /* 

 thick, slightly bent or with a flat spiral curve; sometimes united in long 

 chains. Spores are developed at one extremity of the slightly curved rods ; 

 they are spherical, and the end of the rods containing them presents a sphe- 

 rical enlargement, giving them a comma-like appearance ; terminal flagella 

 have been demonstrated by Koch. 



a b c 



FIG. 244. Vibrio rugula; a, young rods; 6, thicker rods; c, spore-bearing rods. 

 (Prazmowski.) 



X 1,020. 



Biological Characters. The earlier investigators did not determine the 

 characters of growth of Vibrio rugula, but Vignal (1886) has succeeded in 

 cultivating a strictly anaerobic microoganism, obtained by him from the 

 human mouth, which he has described under the same name, although he is 

 not entirely satisfied that it is identical with Vibrio rugula of Prazmowski 

 and previous observers. The biological characters, as determined by the au- 

 thor named, are as follows: An anaerobic, liquefying, motile "vibrio." 

 Movements rotary and progressive. Forms terminal spores, which are rather 

 pear-shaped than round. Upon gelatin plates, in the absence of oxygen, it 

 forms spherical, opaque, yellowish colonies; about the third day the ori- 

 ginal colony is surrounded by a zone of transparent, liquefied gelatin. In 

 gelatin stick cultures, in an atmosphere of hydrogen, development occurs 

 along the line of puncture within twenty-four hours, and a small mass is 

 formed at the point of puncture; at the end of forty-eight hours liquefaction 

 occurs in funnel form ; the liquefied gelatin is clouded, white, and opaque ; 

 later it becomes transparent. In long stick cultures in nutrient gelatin, 

 without exclusion of the air, development occurs only at the bottom of the 

 line of puncture. Upon the surface of agar a white, slightly wrinkled pel- 

 licle, covering the entire surface, is formed in an atmosphere of hydrogen. 

 Development occurs in neutral or in acid bouillon, which becomes diffusely 

 clouded, and from which an abundant white sediment is deposited. Upon, 

 the surface of blood serum a white layer is developed and liquefaction of the 

 medium occurs. Upon potato a wrinkled, white layer is rapidly developed; 



