The Bacterial Diseases of the Bean 49 



Fermi's solution. There is a light cloudy growth in two to three days. 

 The growth is at first white, with a good pellicle. After several weeks 

 a light green color appears, which, however, never becomes distinct. 

 A heavy, stringy, white sediment is formed. 



Conn's solution. There is no growth. 



Potato cylinders. A very light colorless growth appears along the streak 

 in approximately twenty-four hours. In some cases the growth is barely 

 visible. The potato cylinders turn somewhat gray. 



Cellulose digestion. Fair growth is obtained in the broth, but there is no 

 digestion of cellulose. Three strains were tested, all of which had been 

 in culture for approximately a year. 



Starch agar plates (pH 6.6). Plates streaked five or six times, and tested 

 at the end of two, six, and ten days, show no digestion of starch. In 

 determining this, the plates were flooded with a saturated solution of 

 iodine in 50-per-cent alcohol. 



Dextrose broth. A cloudy growth occurs in twenty-four hours in the open 

 arm of a fermentation tube. A light acid reaction appears in one to 

 three days, and gradually fades back to the alkaline side. In some 

 cases there is growth in the closed arm of ^he tube. A pellicle is formed. 

 There is a slight acid production, but no gas. 



Saccharose broth. A light cloudy growth occurs in twenty-four hours. A 

 light acid reaction appears in one to two days, and the medium then 

 gradually becomes alkaline. The color reaction is more vivid in test 

 tubes than in fermentation tubes. Growth occurs sometimes, but not 

 always, in the closed arm of a fermentation tube. There is a slight acid 

 production, but no gas. 



Lactose broth. A light cloudy growth appears in twenty-four hours. There 

 is no further reaction, and no acid nor gas is produced. 



Maltose broth. A light cloudy growth may be noted in twenty-four hours. 

 No acid nor gas is produced. 



Indol production. A good cloudy growth appears in trytophane broth in 

 twenty-four hours. Tests made for indol at the end of one and of 

 four days, by the Ehrlich-Bohme method, were negative. 



Nitrate reduction. The organism does not reduce nitrates to nitrites when 

 grown on nitrate broth and tested at the end of two, four, and eight days 

 with sulfanilic acid and a-naphthalamine in acetic acid. 



Hydrogen-sulfide -production. A very light to fair growth is obtained on 

 Wilson's medium, but the reaction is negative. A good growth is 

 obtained in lead-acetate agar. From a negative reaction to a very faint 

 browning occurs along the stab. 



Chromogenesis. This organism apparently belongs to the green-fluorescent 

 group. Its ability to produce this pigment, however, is weak. The 

 production of a green color, even by recently isolated strains, has never 

 been noticed on beef-extract agar, bouillon, or gelatin. The pigment is 



