1922] 



ROSEN — A BACTERIAL DISEASE OF FOXTAIL 371 



mass 



uninoculated 



cylinders and in cylinders upon which Bacillus Coli was grown, 

 in which the color remained deep blue. 



Nutrient broth plus 1 per cent potato starch. — At the end of 

 11 days, 1 cc. of alcoholic solution of iodine was added and a red- 

 dish blue color developed which disappeared after standing over 

 night. (B. Coli growth remained deep blue). 



Nutrient agar plus 1 per cent potato starch. — Smears were 

 made across the middle on plates containing nutrient agar plus 

 starch. At the end of 10 days plates were flooded with a potas- 

 sium iodide solution resulting in a clear zone about 0.5 cm. wide 

 around the smears, while the remainder of the plates were deeply 

 colored. All 3 of the last experiments reported indicate a strong 

 diastatic action. 



Potato-dextrose agar slants. — Growth good, white, glistening, 

 not viscid but somewhat sticky, best at the base of the slant, no- 

 ticeably flatter than on ordinary nutrient agar, margin even, 

 somewhat spreading. 



Milk. — By the sixth day, at a temperature of 25-30 ° C, there 

 was no coagulation and no clearing. By the eighth day there was 

 a color change from light buff to warm buff (Ridgway). The 

 medium was cleared slowly but there was no coagulation and 

 by the end of 8 weeks most of the fluid was clear, clay-colored, 

 with a somewhat slimy coagulum covering the bottom of the 

 tube which, when agitated, broke up into lumps. At the end 

 of 3 months most of the coagulum disappeared. 



mi 



There was no change in color ud to the fift 



day when the medium began to turn blue at a temperature of 25 

 -30° C. (original color a grayish blue). The behavior was other- 

 wise the same as in plain milk. 



Methylene blue in milk. — Reduction of the dye was prompt; 

 in 24 hours the blue disappeared from the lower two-thirds of 

 the medium leaving a blue rim above. By the end of 48 hours 

 almost all of the blue had disappeared. Here also there was no 

 curdling, indicating that no lab ferment (chymosin or rennin) 

 was produced. This is further indicated by the fact that gelatin 

 was not liquefied. 



Grass decoction agars. — It seemed desirable to test the effect 

 of different grass decoctions on growth, in particular the effect 

 of grass decoction obtained from a susceptible host as compared 

 with a decoction obtained from a resistant host. For this purpose 



