292 J. S. LAWRENCE AND W. W. FORD 



parts remaining unchanged. Clearing progresses slowly, the 

 supernatant fluid persisting as a grayish, pinkish or yellowish 

 muddy medium. After a month at room temperature the 

 medium may becorne very alkahne and turn deep blue-purple. 

 Milk never coagulates. 



Blood serum. Vesicular, dew-drop growth with pink color 

 often very marked, in 24 hours. Vesicles dry down eventually 

 leaving a hard wrinkled growth. Medium is not liquefied. 



Fermentation tubes. Glucose. Turbidity in bowl and arm. 

 Scum formation like that seen in broth. Highly acid. 



Saccharose. Turbidity in bowl and arm with a fragile scum 

 forming from pelhcles in about two days. Acid production but 

 not so marked as in glucose. 



Lactose. Turbidity in bowl and extending up in the arm to the 

 level of the medium in the bowl. Rest of the arm clear. Dense 

 tough scum. Reaction alkahne. 



Thermal death point. Spores survive steaming l\ hours in 

 the Arnold sterilizer. Survive autoclaving up to and including 

 19 pounds pressure but usually destroyed by 20 pounds pressure. 



/ 



Bacillus vulgatus (Flligge) Trevisan. 



Synonomy. Bacillus mesentericus vugatus F'iigge 188G; Bacil- 

 lus vulgatus Trevisan 1889; Bacillus vulgatus Eisenberg 1891; 

 Bacillus vulgatus (Flugge) Migula 1900. 



This organism was first described by Flugge in 1886 (Flugge, 

 1886) and is commonly known as the "potato bacillus." Ac- 

 cording to Chester it is identical with Bacillus suhtilis. By 

 the use of glucose agar and blood serum and by the careful 

 observation of the cultural reactions, particularly in broth and 

 on potato the species is easily separated from this organism. It 

 is fairly common in Baltimore but by no means as frequent an 

 isolation as are many of the other spore-bearers. 



Morphology. Small homogeneous organisms usually distinctly 

 larger than Bacillus suhtilis, measuring 0.5 by 2 to 3 microns. 

 Occasionally short forms 1.125 and long forms measuring 4 

 microns are seen on plain agar. On glucose agar the organisms 



