NON-PATHOGENIC SPIRILLA. 701 



Biological Characters. The same as Spirillum aureum, but the pigment 

 produced is ochre-yellow. Upon a dark background the colonies appear 

 grayish-yellow, on a white ground straw-yellow ; under a low power the 

 deep colonies are first pale-yellow then golden-yellow, and of the same tint 

 throughout, without being darker in the centre ; they are finely granular, 

 with a net-like marking. The superficial colonies under the microscope are 

 pale-yellow with dull-gray spots; on the margin the color usually remains 

 white ; upon the surface of agar an ochre-yellow layer; the same on potato. 



428. SPIRILLUM CONCENTRICUM (Kitasato). 



Found in putrefying blood. 



Morphology. Short spirilla with pointed ends, with two to three spiral 

 turns which are 3.5 to 4 ju in length and 2 to 2.5/< in diameter i.e., each 

 complete spiral ; the filaments are a little thicker than the cholera spirillum ; 

 in bouillon they grow out into long spirals having from five to twenty turns. 



Biological Characters. An aerobic, non-liquefying, actively motile 

 spirillum. Grows best at a temperature of 20 to 23 C. Spore formation 

 not observed. Upon gelatin plates the colonies, by transmitted light, are 

 seen, to be made up of concentric rings, which from the centre to the peri- 

 phery are alternately opaque and transparent ; the contour is round, and 

 from the margin numerous small, spiral outgrowths are given off. In gela- 

 tin stick cultures development occurs principally upon the surface as 

 cloudy layer penetrating the medium to a depth of one millimetre. Upon 

 the surface of agar a diffuse growth which adheres firmly to the culture 

 medium. Upon potato no growth occurs. In bouillon a diffuse cloudiness 

 is slowly developed; later the medium becomes clear and an abundant, 

 slimy deposit is seen at the bottom of the tube. 



429. SPIRILLUM RUBRUM (Von Esmarch). 



Obtained from the putrefying cadaver of a mouse. 



'Morphology. Spirilla about twice as thick as the cholera spirillum and 

 having from one to three spiral turns ; in bouillon grows out into very long, 

 spiral filaments. 



Biological Characters. An aerobic and .facultative anaerobic, non- 

 liquefying, actively motile, chromogenic spirillum. Produces a wine-red 

 pigment in the absence of oxygen only; on the surface of culture media the 



trowth is colorless. According to Lofner, this spirillum has numerous short 

 agella. In old cultures unstained, slightly refractive bodies are seen in 

 the filaments, which appear to be spores. Grows very slowly best at 37 C. 

 Upon gelatin plates small, slightly granular colonies with a tolerably 

 smooth contour are developed at the room temperature; these are at first 

 gray and bluish-red, later wine-red in color. In gelatin stick cultures closely 

 crowded, isolated, spherical colonies are developed along the line of punc- 

 ture ; the growth, except upon and near the surface, has from the outset a 

 beautiful wine-red color. Upon the surface of agar a grayish- white layer 

 of limited extent is developed ; later this has a pink color. Upon potato 

 deep-red colonies the size of a hempseed are developed. 



130. SPIRILLUM OF SMITH. 



Found in the intestine of swine. 



Morphology. Comma-shaped rods and spiral filaments of one and a half 

 to two or even as many as ten spiral turns ; have terminal flagella. 



Biological Characters. An aerobic, non-liquefying, motile spirillum. 

 Grows at the room temperature. Upon gelatin plates, at the end of thirty- 

 six to forty-eight hours, small, spherical, finely granular colonies are de- 

 veloped, which have a brownish color; and upon the surface small, round 

 colonies with a somewhat irregular contour. In roll tubes, when the colo- 



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