720 ADDITIONAL SPECIES OF 



and found by Freudenreich to produce an abnormal fermentation of cheese, 

 characterized by the presence of large cavities (" boursouflement ") and by 

 a very bad taste. 



BACILLUS . 



Morphology. Varies considerably in size, and may resemble a micrococ- 

 cus in form ; usually 1 /* broad and 1 to 2 V long. 



Stains with the usual aniline colors, but rather feebly ; does not stain by 

 Gram's method. 



Biological Characters. An aerobic and facultative anaerobic, slightly 

 motile, non-liquefying bacillus. Spore formation not observed. Grows in 

 the usual culture media at the room temperature. Upon gelatin plates the 

 deep colonies are spherical, granular, and yellowish in color; upon the sur- 

 face they are round and granular at first, later they become opaque and re- 

 semble a drop of wax. In gelatin stick cultures development occurs all 

 along the line of puncture, and upon the surface a whitish layer is formed. 

 Upon agar a grayish white layer is developed. Upon potato a thick, yel- 

 lowish layer is formed; this is viscid and contains numerous gas bubbles. 

 In milk coagulation is produced at the end of twenty-four hours, and an. 

 abundance of gas is given off. In bouillon containing milk sugar it mul- 

 tiplies abundantly and a large quantity of gas is liberated. Grows best at a 

 temperature of 30 to 35 C. Thermal death-point 60 C. fifteen minutes' 

 exposure. 



BACILLUS b. 



Morphology. Resembles bacillus a; bacilli from 1 to 2 /* long and about 

 1 p thick. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, motile bacillus. Is differentiated from a by the fact that it causes lique- 

 faction of nutrient gelatin after an interval of several weeks, and by the fact 

 that the young colonies upon gelatin plates are quite viscid. Spore forma- 

 tion not observed. Thermal death-point 80 C. five minutes' exposure. 

 An abundance of gas is given off from cultures containing milk sugar. 



BACILLUS C. 



Morphology. Short bacilli ; often oval or even spherical in form ; about 

 1 n long. 



Biological Characters. An aerobic, non-liquefying bacillus. Spore 

 formation not observed. Upon gelatin plates colonies are developed which 

 resemble those of bacillus a, but are more coarsely granular ; the colonies 

 are very adherent and difficult to remove from the culture medium. Upon 

 agar a viscous, white layer is developed. Upon potato the growth is of a 

 yellowish- white color and similar to that of a and b, with gas bubbles; it is 

 very adherent. In liquid media the growth of this bacillus causes the cul- 

 ture liquid to become extremely viscous and almost gelatinous in consistence. 

 In milk coagulation occurs at the end of sixty hours at 37 C., and the rnilk 

 then loses its viscosity. 



471. MICROCOCCUS FREUDENREICHI (Guillebeau). 



Obtained from milk which had undergone viscous fermentation. 



Morphology. Micrococci having a diameter of 2 /*, solitary or in chains. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing micrococcus. Grows best at a temperature of 20 C. Upon gelatin 

 plates made with milk serum, punctiform, granular colonies are developed 

 at the end of thirty-six hours ; when touched with the platinum needle these 

 may be drawn out into long threads; soon after the gelatin commences to 

 liquefy and becomes very viscous. Upon potato the growth is sometimes 



