686 NON-PATHOGENIC BACILLI. 



Morphology. Bacilli with square ends, from 1.4 to 3/< long; often united 

 in pairs, the elements of which may be joined at an angle of greater or less 

 degree. 



Biological Characters. An aerobic, liquefying bacillus. Spore for^ 

 mation not observed: Motility not mentioned. Grows at the room tempera- 

 ture in the usual culture media. Upon gelatin plates, at the end of forty- 

 eight hours, small, round colonies are developed, which increase considerably 

 in thickness and diameter, and by the fourth or fifth day have caused lique- 

 faction of the sm*roundiiig gelatin. In gelatin stick cultures, at the end of 

 forty-eight hours, a small mass has formed at the point of inoculation, and a 

 scanty line of development is seen along the track of the inoculating needle ; 

 by the fourth day the growth has extended over the entire surface and pre- 

 sents a decided prominence at the centre ; the gelatin below is liquefied and 

 remains transparent, with some opaque, white flocculi in suspension ; by the 

 twelfth day the liquefaction extends to a depth of two centimetres, and a 

 yellowish- white, abundant deposit is seen at the bottom. Upon the surface 

 of agar at 36 to 38 C., small, white, opaque colonies are developed, which 

 present a small, nipple-like projection at the centre. In neutral bouillon a 

 diffuse cloudiness is produced ; a thick, dull- white layer forms upon the sur- 

 face, and an abundant dull-white deposit is seen at the bottom of the tube. 

 Does not grow well in acid bouillon. Upon potato a rather thick growth is 

 developed, which extends slowly and acquires a slightly pinkish tint. . 



399. BACILLUS HAVANIENSIS LIQUEFACIENS (Sternberg). 



Obtained in cultures from the sui'face of the body of patients in the char- 

 ity hospital at Havana. 



Morphology. Bacilli with round ends, about 0.8 /* thick and varying 

 greatly in length from 1.2 to 5 /< ; solitary, in pairs, or may grow out into 

 long filaments. 



Biological Characters. An aerobic, liquefying, motile bacillus. Spore 

 formation not observed. Grows at the room temperature better at 37 C. 

 Upon gelatin plates, at the end of twenty-four hours at 22 C., round colo- 

 nies are developed which have a milky opacity and are surrounded by a 

 transparent marginal zone with irregular margins; under the microscope 

 these colonies are seen to be finely granular ; at the end of twenty-four 

 hours liquefaction commences. In gelatin stick cultures liquefaction occurs 

 along the entire line of puncture; at the end of four days the liquefied gela- 

 tin is clouded throughout ; in old cultures it is quite transparent, and a slight 

 flocculent deposit is seen at the bottom of the tube. Upon the surface of 

 agar, at the end of two weeks, a thin, pale-brown layer is developed. No 

 growth upon potato. Not pathogenic for rabbits. . 



400. BACILLUS LIQUEFACIENS COMMUNIS (Sternberg). 



Obtained in cultures from the faeces of yellow-fever patients at Decatur, 

 Ala. (1888). 



Morphology. Bacilli with round ends, from 1 to 2 {t long and about 0.7 /< 

 thick ; solitary or in pairs. 



Biological Characters. Anaerobic and facultative anaerobic, liquefy- 

 ing, actively motile bacillus. Grows in the usual culture media at the room 

 temperature, also at comparatively low temperatures, and in th i incubating- 

 oven at 37 C. Spore formation not observed. Grows in an acid medium 

 1 : 500 of hydrochloric acid. In gelatin stick cultures liquefaction occurs 

 rapidly in the form of a purse. On potato, at the end of t\vo weeks, an ir- 

 regular, corrugated layer is developed which has a pinkish color. Not 

 pathogenic for rabbits. 



