A Bacterial Disease of Stone Fruits 407 



control. These cultures were under observation for thirty-two days, but 

 no growth was observed in any of the tubes. 



Nitrogen nutrition. — In filtered river water containing one per cent 

 of asparagin, the organism made a slow initial growth first visible in six 

 days. When distilled water was used the first signs of growth failed to 

 appear before the tenth day, and in some cases as late as the fifteenth 

 day, even when the strongest, oldest cultures were used. A very slight 

 growth was obtained in river water containing only dextrose. River 

 water alone failed to give any growth. 



Nitrates. — Twelve tubes, each containing ten cubic centimeters of 

 peptonized beef broth to which had been added one per cent of nitrate 

 of potash, were divided into four lots of three tubes each. The solutions 

 in each lot were then inoculated with apricot, nectarine, peach, and 

 plum strains, respectively. 



At the end of ten days the tubes were clouded and a tube from each 

 lot was tested for nitrates in the following manner: To each culture one 

 cubic centimeter of boiled starch water and one cubic centimeter of 

 potassium iodide solution (1-200) were added. A few drops of sulfuric 

 acid were then introduced. The peach and plum cultures gave a slight 

 blue reaction, and on the twentieth day the remaining tubes each gave a 

 distinct reaction. However, six months later these experiments were 

 again repeated three times, with the same strains of the four organisms, 

 and not a single culture gave the reaction. 



Indol. — A number of tubes of Uschinsky's solution with the addition 

 of one per cent of Witte's peptone were inoculated with a five-days-old 

 agar culture. Apricot, nectarine, peach, and plum strains were used in 

 making these inoculations. The inoculated tubes all showed considerable 

 growth on the fifth day, but a test for indol was not made until the tenth 

 day. Sulfuric acid water (1-2) and dilute sodium nitrate (1-200 in water) 

 were used. On the tenth day all cultures gave a slight rose color after 

 being placed in boiling water for two minutes, indicating indol production. 

 The other tubes were tested twenty days later and a well-marked indol 

 reaction was obtained from all the cultures. 



Cultures of the four strains made in Dunham's peptone solution gave 

 positive results at the end of twenty days. There was a trace of pink 

 before heating, and after four or five minutes in a water bath at 80° C. 

 the reaction became distinct. 



