GENUS BACILLUS 35S 



of two or more layers, outside of which is a zone of a single- 

 layer, from which amoeba-like processes extend upon the sur- 

 face of the gelatin. These processes are constantly undergoing 

 changes in their form and position. The young colonies deep 

 down in the gelatin are somewhat compact, and rounded. 

 Later they form irregular, radiating masses, and simulate the 

 superficial colonies. It is difficult to describe all the forms 

 which the Bacillus proteus takes in the various stages of its 

 growth on gelatin plates. "When the consistency of the medium 

 is more solid, as in 10% gelatin, the liquefaction and migration 

 of surface colonies are more or less retarded. In gelatin-stick 

 cultures the growth is less characteristic liquefaction takes 

 place rapidly along the line of puncture, and in a short time 

 the entire contents of the tube are liquefied. 



Potato. A dirty yellowish growth appears. 



Serum. It is stated that some strains will liquefy con- 

 gealed serum. 



Bouillon. It produces a uniform cloudiness in the liquid. 

 In some cultures a pellicle is formed. It ferments dextrose 

 and saccharose with the formation of gas but it does not fer- 

 ment lactose. 1 



Milk. Milk is coagulated.* The reaction becomes more 

 acid. 



Life conditions and properties. Bacillus proteus is an 

 aerobe and facultative anaerobe. It grows at room tempera- 

 ture. Its maximum growth seems to occur at about 24 C. but 

 it multiplies readily at 37 C. It produces a ferment which 

 liquefies gelatin and dissolves coagulated casein. It produces 

 indol and phenol. It multiplies in urine decomposing urea.** 



1 Smith. The Wilder Quarter Century Book, p. 212. 



* There is a wide discrepancy in the findings of different work- 

 ers on this point. It is possible that different strains may act dif- 

 ferently. 



** Horton Smith (Jour, of Path, and Bact.) has described an 

 organism as Bacillus proteus urinae which he isolated from a case 

 of cystitis. It grew aerobically on all the ordinary media and was 

 also a facultative anaerobe. It grew more rapidly at a temperature 

 of 37 C. It resembles very closely B. vulgaris. It was pathogenic, 

 for guinea pigs. 



