106 CROWN-GALL OF PLANTS. 



Other slides made at various times and measured February 25, 

 1910, gave the following results: 



(1) Van Ermengem: Average diameter 1.2//; some less, a few 

 more. Result on a second slide: Average diameter 1 to 1.2/z. 



(2) Pitfield's (Smith), agar 24 hour: Average diameter 1.2/t, 

 widest 1.75/1, narrowest 1/x. Occasionally Y-shaped rods. Pit- 

 field's (Bro%\Ti): Widest diameter 1.1ft; many less wide, i. e., 0.8 

 to O.Qfi. 



(3) Carbol fuchsin, without a mordant (30 minutes) flagella visible: 

 Average diameter 1.2/i. 



(4) Lowit's stain: Average diameter 1.56/«, 



(5) Loeffler's flagella stain (1909): Diameter 0.8 to Ijjt; none seen 

 wider than lu. 



In making these measurements a Zeiss photomicrographic stand, 

 3-mm. apochromatic oil-immersion objective, No. 12 compensating 

 ocular, and Schraubenmikrometer were used (Smith). 



The rods are straight, have rounded ends, thin walls, and a uni- 

 form diameter. 



When taken from young agar cultures, the limits of size are 1 to 3 

 by 0.4 to l.Sju. Size of the majority 1.2 to 2.5 by 0.5 to 0.8 fx. Occa- 

 sionally one finds more than two rods attached, end to end, forming 

 short chains (seldom more than 3, or 4 elements). Long chains have 

 never been observed in the daisy organism except under abnormal 

 conditions, e. g., in old 3.5 per cent salt bouillon, where sinous or 

 curved rods 20 times the ordinary length were seen. 



Endospores (?). — No endos pores have been observed, and yrohably 

 none occur. Certainly they are not formed under most culture condi- 

 tions, as shown by the short life of cultures and by their sensitiveness 

 to heat. The following additional experiments were made in 1910: 



Bouillon cultures some weeks old were boiled for 3 minutes with the 

 result that all were killed. The experiment was repeated after some 

 months with the same result. Bouillon cultures were then heated 

 for 20 minutes at 80° C, after which some grew. It was thought 

 that owing to the lumpy character of the slime the heat might not 

 have penetrated to the center of all the pseudozoogloeee. The experi- 

 ment was repeated, therefore, exposing the tube for 60 minutes at 

 80° C. x\fter this none of the transfers grew, not even when large 

 quantities of the fluid were used (1 drop, 2 drops, etc.). 



Flag (Ma. — Tlie organism is motile hy means of a polar fiagellum 

 Sometimes 2 or 3 terminal flagella are present, but more often in the 

 slides examined there was only 1. The rods of young cultures 

 show a distinct movement when examined in hanging drops. The 

 flagella were first stained by the senior writer from 24-hour agar cul- 

 tures, using Pitlield's flagella stain (lig. 1, a). Afterwards they were 



213 



