408 Report of the Mycologist op the 



was inoculated by placing in the drill, at the time of planting, a 

 liberal quantity of soil in which diseased plants had grown the 

 preceding season. Not a single plant developed the disease. 



Pop corn, also, has resisted all attempts at inoculation. In 

 1897 a 50-foot row of pop corn, variety Maple Dale,, was inocu- 

 lated by putting diseased soil in the drill at time of planting. 

 None of the plants became diseased. On July 8, 1897, twenty 

 plants of the same variety of pop corn were inoculated by punc- 

 turing the stem and inserting diseased tissue into the wound as 

 in the experiments with sweet corn and field corn. None of the 

 plants became diseased, but as in the case of field corn the germ 

 could be seen in some of the bundles up to the third node. 



Oats inoculated by means of diseased soil, and teosinte 

 (EucJiloena luxurians), inoculated both by puncture and diseased 

 soil gave negative results. i ' 



DESCRIPTION OF THE GERM. 



Morphology. — A short bacillus with rounded ends; usually oc- 

 curring in pairs with a plain constriction between the members. 

 A pair varies in length from 2.5 microns to 3.3 microns, and in 

 width or diameter from .65 micron to .85 micron. (See Plate 

 XVI, fig. 1.) No spores have been observed, but since an ex- 

 tended examination of old cultures has not been made it can not 

 be stated with certainty that spores are not formed. The organ- 

 ism is plainly motile but not actively so. 



Groicth on agar. — The organism grows readily on neutral agar 

 of the following composition: Finely chopped beef, 500 grams; 

 Witte's peptonum siccum, 5 grams; agar, 15 grams; water, 1 

 liter; made neutral with sodium carbonate. In Petri-dish cul- 

 tures on this medium the colonies become plainly visible within 

 forty-eight hours at a temperature of 22° to 25° C. The buried 

 colonies soon become spindle-shaped, while the surface colonies 

 are circular and with nearly smooth outline. From the very 

 start the colonies have a light yellow color which deepens to light 

 orange-yellow in the course of about a week. The surface colon- 

 ies are smooth and shining and show no tendency to spread 



