108 



CEOWN-GALL OF PLANTS. 



It does not stain by Gram. It stains readily a uniform deep blue 

 if amyl alcohol be substituted for ethyl alcohol in the washing after 

 exposure to the anilin gentian violet and the iodine-potassium 

 iodid of Gram's stain. 



Taken from beef bouillon 7 weeks old it did not show glycogen 

 stain when exposed to iodine water; i. e., there was only a uniform 

 yellow color. 



It is not acid-fast. 



Brizi's method was employed on daisy galls without success. By 



the use of methylene green 

 (not methyl green, but that 

 was tried also), without sub- 

 sequent exposure to acid, 

 numerous cell inclusions, con- 

 sisting of bacteria-like gran- 

 ules, were demonstrated, but 

 whether really bacteria re- 

 mained undetermined. 



The bacteria Brizi suc- 

 ceeded in staining readily in 

 poplar tumor tissues by an 

 acid-fast method were probably not this organism. In our hands 

 the gall-producing organism in American poplar galls stains like 

 the daisy. It is not an acid-fast organism. 



In sections it is often stained with difficulty, and we have seldom 

 been able to differentiate it well from the surrounding tissue. It 

 seems to us to occur, for the most part, at least, in the interior of the 

 parenchyma cells rather than in the intercellular spaces or vessels. 

 Repeated efforts to stain in situ have not yielded, as a rule, well- 

 stained, sharply defined rods such as one would expect, but occa- 

 sionally stained and unstained we have seen rods inside the cells 

 which we believe to be the bacteria. 



Fig. 3. — Daisy organism. Slime from pellicle on beef- 

 bouillon culture three weeks old. Stained with carbo! 

 fuchsin, and camera-drawn by Miss Brown. 



CULTURAL CHARACTERS. 



NUTRIENT AGAR.'' 



Colonies. — ^VJien the organisms are obtained from a crushed Tcnot 

 the colonies come up in from 3 to 12 days (usually 4 to 6) at a room 

 temperature of about 25° C. on poured agar plates. They come 

 up very much slower when taken from knots than when taken 

 from young cultures. The white smooth surface colonies are circular 

 with an even margin, rounded up to the center, and have a shining 

 semitransparent luster. The colonies increase in size slowly at 25° C, 



213 



o -1-15 poptouizcd beef bouillon with 1 per cent Merck's agar flour. 



