THE MULBERRY BLIGHT.' CULTURAL CHARACTERS 355 



clearing, keeping uninoculated tubes for comparison; after 10 

 weeks examine under the microscope for general appearance, 

 comparing with one of the check tubes). Growth in Cohn's 

 solution (there should be none or very little). Growth in 

 Uschinsky's solution (which should be copious). 



Behavior in fermentation tubes in peptone water (Why not 

 in beef bouillon?) containing various sugars and alcohols (which, 

 of course, must be pure). Any growth in the closed end? 

 Any acids formed in the open end? 



' 



- > i > - ."' 



FIG. 273. Flagellate rods of Bacterium mori. Stained by van Ennengem's 

 method from a 2-day agar streak. James Birch Rorer's isolation. X 1000. 



Determine production of indol using Bacillus coli for com- 

 parison and testing at end of 10 days and 20 days (heat the 

 tubes in a water bath at 80C. for five minutes, if necessary). 



Non-nutritional Environment. Minimum temperature for 

 growth (try first at 2C.)? Maximum temperature (try first 

 at 34C.)? Can you obtain any growth at 1C. or at 37C.? 

 Optimum temperature (try first in peptone bouillon at 27, 30, 

 and 33C., inoculating copiously from bouillon and examining 

 every 3 hours)? Is the organism sensitive to dry air (to have 

 all the bacteria freely exposed, use young bouillon cultures)? 

 Effect of sunlight (expose on ice for 10, 20, 30, and 40 minutes 

 in thin-sown agar-poured plates, preferably after a storm, i.e., 



