AEROBIC SPORE-BEARING NON-PATHOGENIC BACTERIA 501 



Blood serum. Fairly profuse moist glistening smooth whitish 

 growth. Some softening of the serum but no definite liquefac- 

 tion. 



Fermentation tubes. Glucose: a sUght turbidity in the bowl 

 and neck with a reduction of the Htmus in the closed arm. Re- 

 action acid. 



Saccharose : a similar growth with an acid reaction. 



Lactose: only a slight turbidity develops with an alkaline 

 reaction. 



Thermal death point. The spores survive 20 pounds pressure 

 in the autoclave but are destroyed by 22 pounds. They sur- 

 vive one hours steaming in the Arnold. 



Bacillus panis Migula 1900 



This organism was originally described by Vogel (1897) as 

 Bacillus mesentericus panis viscosi I. It has been found in Bal- 

 timore, but once, in dust. 



Morphology. When first isolated this organism showed only 

 encapsulated forms, the capsules staining readily with gentian 

 violet. As the organism was cultivated on artificial media in 

 the laboratory it lost its capacity of forming easily-stained 

 capsules but continued to manufacture a quantity of viscous ma- 

 terial which gave a characteristic appearance to the cultures. 

 In young cultures on plain agar, 6 to 24 hours old, the organisms 

 are small and homogeneous with round to flattened ends, meas- 

 uring 0.375 to 0.5 by 1.5 to 3 microns. They show no appreci- 

 able difference in thickness on glucose agar, but tend to show 

 long forms measuring 5 to 6 microns in length. Occasional 

 shadow forms are seen measuring 0.75 to 1 by 1.5 to 4 microns. 

 (Figures 60, 61, and 62.) 



Motility. No motihty has thus far been demonstrated. 



Staining properties. Gram-positive. 



Spore formation. When first isolated, spores were formed early, 

 often in 24 to 48 hours. After long cultivation in the laboratory, 

 they appear in the cultures only after 6 to 8 days growth. They 

 are formed in the centers or towards one end of the rods and are 



