286 GRASSES OP IOWA. 



This organism is described by Moore* as follows: 



Morphology.— A motile bacillus varying in length from 1.8 to 

 2", ends rounded. Appears in cultures singly or united in 

 short chains or clumps. From five to fourteen flagella have 

 been demonstrated. It stains readily with aniline dyes. 



Cultural characters. — It develops a grayish, somewhat vigor- 

 ous, glistening, non-viscid growth on the surface of agar. In 

 the depth of agar it is more feeble. Gelatin is softened along 

 the needle track and beneath the quite vigorous grayish growth 

 which appears on the surface at the end of six days. It lique- 

 fies very slowly. The liquid gelatin is clear, with a viscid 

 grayish sediment and strongly alkaline in reaction. On potato 

 a dull grayish, non-viscid growth appears within twenty-four 

 hours. In alkaline Douillon the multiplication is quite active, 

 the liquid becoming heavily clouded in twenty-four hours. The 

 casein of milk is coagulated in about eighteen days. It pos- 

 sesses active fermentative properties. . In the fermentation 

 tube, when filled with bouillon containing 2 percent dextrose, 

 the closed bulb is filled with gas in forty eight hours. The 

 liquid is very acid in reaction. The gas consists of 72 per 

 cent COg and 28 per cent H. In a similar tube containing sac- 

 charose the fermentation is quite as active, but the proportion 

 of the gas constituents is different, being 66 per cent CO, and 

 34 per cent H. In bouillon containing lactose the closed bulb 

 of the tube is not filled with gas until the fourth day. The gas 

 is practically the same as that produced in the saccharine 

 bouillon. 



Burrill supposed the organism to be widely distributed. 

 Moore also observed the disease in Maryland and Indiana, and 

 some of the organism has been isolated here at Ames. The 

 general characters certainly correspond, and diseased material 

 submitted to Burrill had bis verification. Cultures made by one 

 of us and compared with his indicated its presence here. The 

 dwarfed condition mentioned by Burrill was especially pro- 

 nounced in one field of corn grown in bottom land. This field 

 has since been planted with mangolds, turnips, alfalfa, and 

 beans, besides receiving a heavy coating of various fertilizing 

 material. In year 1897 it had an exceptionally fine crop of 

 corn. It may be that this root trouble is due to an entirely dif- 

 ferent cause, as has been suggested by Moore. 



*1. C. p. 46. 



