E. ML Doidge 17 



surrounding spaces were crowded with bacteria, numbers of which were 

 lying in close contact with the lignified walls. 



In the section represented in Plate VIII a number of yeasts were 

 visible in the broken down cells of the surface tissues, but were not 

 present in very great numbers. 



For this reason, the infections in the stem very soon cease to increase 

 in size, and can only take place near the growing tip. The diseased 

 spots in the leaf are bounded by some of the smaller veins. 



Morphology of the organism. Dimensions. 



The organism is a short rod with rounded ends, varying considerably 

 in size on different media. 



In the host plant it measures from -8/z to 2-6 /x, by '5/x to *7 [x. The 

 majority are 1-5 to 1-8/x by -6/x. 



In a preparation made from a 24 hours old culture on nutrient agar 

 (—15 Fuller) and stained with aqueous Gentian Violet, the limits of 

 length were -9//, and 2*7//,; the breadth varied from -5 to -1 [x. The 

 average was 1-5 fx x -6 fx. The following are some actual measurements: 



1-5/j. x -6/j. 2-4/jl x -lii 



l-6/i x -6/i l-6/i x -6/i 



2-24(1 x -6fi* 2-3/x x -G/i* 



1-4(1. x -5(i 2-lfi x -§/x* 



l-4/i x -6/i -9(i x -6(1, 



The rods marked * were just about to divide, and the last in the list 

 was the result of a recent division. 



In beef broth cultures 21 — 24 hours old, short rather thick forms 

 predominate; the rods measure -9 to 1-4/a x -6 to -8//,. The following 

 are some actual measurements taken from a preparation stained with 

 carbol fuchsin: 



2-lfi x -8/1 l-4(i x -8(i 



•9/i x -8(i 1-lfi x -6(i 



•9m x -7/i 



In gelatine cultures the rods are exceptionally small, the majority 

 measuring -9 to lju, by -5 to -6/x. In slides made from a gelatine plate 

 culture three days' old, the longest observed were only 1*6 /x. 



In solutions containing large percentages of sodium chloride, e.g., 

 beef broth containing 7 to 8-75 % NaCl the organism grows out into long 

 threads which are very variable in length and thickness (Plate XIII, 

 fig. a). They are not septate, and a drop from a beef broth culture 

 containing 7 % NaCl examined with the paraboloid condenser showed 



Ann. Biol, ii 2 



