CULTURAL CHARACTERS OF THE DAISY ORGANISM. 109 



attaining their maximum size of 2 to 4 mm. in thin-sown phites in 

 from 2 to 4 days after becoming visible. They attain a larger size on 

 culture media after many transfers than when first plated from the 

 galls. The colonies, especially when they pile up in the center, are 

 opaque, but never of a chalky white. They often resemble the 

 watery colonies of some forms of the root-tubercle organism of 

 legumes. Plates poured from a .voung bouillon culture show colonies 

 sometimes in 24 hours, and nearly always in 48 hours at 25° C. Old 

 colonies are sometimes iridescent. 



Streaks. — Needle stroke not wide-spreading and very translucent at 

 first. On slant agar ( + 15) the streak made with a platinum needle 

 has a moderate filiform growth and does not branch on the surface 

 nor penetrate the agar. The white streak widens slowly (chiefly 

 toward the bottom), is slightly to considerably raised, sometimes 

 nearly convex in cross section, and has a glistening luster; it is 

 opaque or translucent and is slightly opalescent; is free from odor, 

 somewhat slimy (especially after the first two or three days), and 

 does not color the agar upon which it grows — at least not for some 

 weeks, after which it may sometimes show a slight brownish color. 

 In one strain ( 1909) the old slime, especially where it had run down 

 into the V, had a trace of brownish in it lighter than Ridgway's 

 tawny olive and somewhat resembling his buff or cream buff. 

 This culture looked suspicious, but proved pathogenic. This has 

 happened a number of times. The rods taken from this substratum 

 stain readily with carbol fuchsin, gentian violet, meth3dcne blue, or 

 anilin methyl violet. 



Two streaks from "B, " made February 14, 1907, on slant 6 per 

 cent glycerine agar by use of a loop, covered at the end of 48 hours 

 the whole surface of the agar with a smooth, wet-shming growth, 

 which was white by transmitted light. This growth was slightly 

 viscid and plainly alkaline. There was no stain of the agar, nor were 

 there any crystals. The cultures were pathogenic, as shown by inocu- 

 lations of February IS on daisy, tomato, and tobacco (Smith). 



Stah. — Nontypical in stab cultures. The growth is filiform and best 

 tov.'ard the top of the stab; the surface growth is scanty to abun- 

 dant and generally restricted. Agar is not liquefied nor softened. 



CORN-MEAL AGAR. 



Feehle growth at end of Jive days. This experiment was repeated 

 twice with the same result — growth at the end of four weeks was 

 very slight, the media being made by the same formula, but in another 

 laboratory. 



POTATO. 



On sterile potato cylinders (lower end in water) the organism malces 

 a much more rapid growth than on agar. The growth is first visible 



213 



