408 BACTERIAL DISEASES OF PLANTS 



from flask cultures, wash free from organic matters and test 

 them qualitatively for the presence of magnesium, phosphorus 

 and ammonia. 



Describe its behavior in bouillon, and nitrate bouillon. 

 Test 10-day and 20-day-old peptone water or peptone-bouillon 

 cultures for indol, using Bacillus coli for comparison. Study 

 its behavior on potato and other cooked vegetables and make a 

 note of any striking appearance not here recorded. Do the 

 potato cultures yield a brownish stain? Are they viscid? 



Determine behavior of organism in peptone water in fermen- 

 tation tubes with various sugars and alcohols (these fluids should 



FIG. 314. Agar-poured plate of Bacterium savastanoi insolated 30 minutes 

 in April, 1908, and photographed 5 days later. The colony-side was covered 

 as far as the line with folds of black paper. 



be titrated and corrected to +15 on Fuller's scale). After a 

 week, pipette out the cloudy fluid from the open end of the 

 tubes containing dextrose and titrate with phenolphthalein and 

 N/20 sodium hydrate; then remove the clear fluid from the 

 closed end and titrate as before. Any difference? Try com- 

 parative streaks on peptone litmus agar, having previously 

 added to some tubes 5 per cent cane-sugar and to others 5 per 

 cent dextrose. Any difference in color-reaction or in volume 

 of growth? What is the acid formed from grape sugar? 



