22 A SOFT ROT OF THE CALLA LILY. 



The second preparation was the same as the first, except that it con- 

 tained 1 per cent of grape sug-ar. Three days after inocuhition there 

 was no ai)parent change in color, but at the end of tive days the inoc- 

 ulated tubes had a greenish tinge. This became more distinct from 

 day to day for several weeks, and at the end of two months the inocu- 

 lated tubes were entirely green, while the control tubes remained blue. 

 The blue color of the inoculated tubes was not restored upon shaking. 



Steamed potato cijtituLrs.—Voi'Aio cylinders were sterlized by steam- 

 ing on three consecutive days in the stei'ilizpr. Some of these were 

 inoculated with a 1-mm. loop of a 24:-hour-old culture of the calla-rot 

 organism in beef broth. Twenty-four hours after inoculation the 

 organism had spread over about two-thirds of the slant surface of 

 the inoculated cylinders. The rate of growth was slow as compared 

 with that on other media. The surface of the growth had a shiny 

 appearance and a faint tinge of yellow which corresponded very closely 

 to Ridgway's Cream Color, No. 20, Plate VI, or Saccardo's Cremeus, 

 No. 27, Table II. The inoculated cylinders began to turn gray toward 

 the inoculated ends. Even in twenty-four hours the discoloration 

 extended from one-third to two-thirds of the length of the cylinders. 

 The color deepened from day to day until at the end of two weeks the 

 upper ends of the cylinders were distinctly brown, the color fading 

 into a gray toward the lower ends of the cylinders. All the many 

 inoculated cylinders retained their shape, and the control cylinders 

 remained firm and white throughout the experiment. 



In testing the potato cylinders for starch the reaction was immedi- 

 ate in both the inoculated and the control cylinders and the color 

 was nearly the same, but less purple and more blue in the control 

 than in the inoculated tubes. These tests were made at the end of 

 the second week and later. The odor of the inoculated cylinders at 

 the end of two weeks was sour and disagreeable, resembling spoiled 



paste. 



Raw potato.— A fairly smooth potato was selected and thoroughly 

 washed with tap water to remove the surface dirt. It, was then 

 washed with distilled water and the surface was sterilized with a solu- 

 tion of corrosive sublimate (1 part in 1,000), after which it was rinsed 

 with sterile water. It was then cut with a sterilized knife into 

 slices about 2 cm. in thickness. Each slice was divided into four 

 parts and placed in a deep sterilized petri dish. Several petri dishes 

 were prepared in this manner. Two of the pieces in each were inocu- 

 lated with a 24-hour-old beef-broth culture of the calla organism by 

 Y)lacing several drops of the beef-broth culture on the surface of the 

 pieces and then stabbing through these drops into the potato with a 

 sterile needle. Two pieces were left for control. In twenty-four 

 hours the inoculated and control pieces showed a slight discoloration 

 owing to the action of the air, but only the inoculated pieces decayed. 



