48 THE ROYAL SOCIETY OF CANADA 



Potato Slant. 



No growth occurs. 



Milk. 



Very slow growth. No change in appearance occurs until after 

 two weeks at 25°C. Later a brownish, slight, flaky pellicle develops 

 and the milk slowly clears without coagulation. 



Litmus Milk. 



An alkaline reaction is slowly produced, the medium being deep 

 blue after six weeks. 



Loeffler's Blood Serum. 



Moderate growth occurs, slightly raised, linear-spreading, echin- 

 ulate, glistening, rugose surface, compact. The growth is greater than 

 on beef extract agar but not so great as on Ashby's agar. 



Smith Fermentation Tube Cultures. 



There is no gas and no acid produced by any of the four varieties 

 in peptone water plus the various sugars called for in the chart of the 

 American Society of Bacteriologists. There is growth — finely to coarsely 

 granular in the open bowl in each case, but no growth in the closed 

 arm. The greatest growth occurs in the mannite solution and the 

 least in glycerine. 



Nitrate Broth. 



There is slight growth, but no reduction to nitrites or ammonia. 



Uschinsky's Solution. 



There is clouding and formation of a light, flaky pellicle. 



Cohn's Solution. 



A slight growth occurs. 



Fermi's Solution. 



There is clouding and formation of a light pellicle. 



Morphology. 



The morphology of the organisms in each variety varies very 

 considerably with age and cultural conditions. On Ashby's media, 

 young cells from 24 to 48 hours old cultures appear mostly as motile, 

 short, thick rods with rounded ends, 2-4/^ x 5-10//, in ones, twos, 



