516 C. A. LAUBACH, J. L. RICE AND W. W. FORD 



predominating types isolated from these latter sources were also 

 found predominating in soil, since the 520 cultures revealed only- 

 one new species. 



^ Bacillus agri nov. sp. 



This organism was isolated on two occasions from Baltimore 

 soil and cannot be identified with any previously-described spe- 

 cies. It evidently belongs in the Simplex-cohaerens group and 

 because of its different cultural reactions must be described as a 

 new species. 



Morphology. Large uniform homogeneous rods with round 

 ends measuring 0.625 to 0.75 by 2.5 to 5 microns in young cultures 

 on plain agar. Occasionally chains with a number of elements 

 are found and shadow or transparent forms measuring 12-15 

 microns in length. On glucose agar there is no special change in 

 morphology, but the proportion of shadow forms is greater. The 

 morphology resembles that of Bacillus simplex. (Figures 73 and 

 74.) 



Motility. Active motility in young cultures. 



Staining properties. Gram-positive. 



Spore formation. Spores begin to form within 24 hours but 

 are not abundant till after the lapse of three or four days. They 

 are central or slightly ex-centric, no wider than the rods from 

 which they spring. The free spores retain rims of protoplasm 

 for some time. They measure 0.625 to 1.125 to 1.25 microns. 

 As they lose their protoplasm they become more oval and 

 measure 0.5 to 0.625 by 0.75 to 1.125 microns. The spore-for- 

 mation resembles that of Bacillus simplex. 



Agar slant. Fairly profuse gray moist smooth glistening 

 opaque growth along the line of inoculation with a slight tendency 

 to spread. 



Agar stab. Faint granular growth along line of inoculation. 



Agar colonies. Small gray moist glistening elevated colonies 

 with opaque centers. No tendency to spread. 



Glucose litmus agar. Fairly profuse gray moist smooth glis- 

 tening opaque growth with a slight tendency to spread. The lit- 

 mus is completely reduced within 48 hours with a very slight 



