Feb. 16. 1920 Basal Glumerot of Wheat 545 



Striae, often coarse, sometimes even "fish-scale" in character, may be 

 seen in the margins. A halo forms about the colonies. These halos are 

 not cleared areas, but rather a whitish clouding fading gradually into 

 the unchanged medium of the plate. In crowded plates this clouding so 

 quickly coalesces that no halos are observed. After five or six days the 

 colonies have a zoned appearance, the centers and borders being rather 

 white, separated by a greyish zone. The internal marks are finer and 

 more like those seen in beef agar. 



Agar stabs. — Surface growth only moderate, white, moist, and 

 shining. Slight mesenteric growth in the upper part of the stab, but 

 this does not persist. Old cultures show only surface growth. The 

 whole medium becomes pale yellowish green ("Bright Chalcedony 

 Yellow").* 



Agar streaks. — The growth is white, thin, transparent. The medium 

 greens in 24 hours. The surface is very slightly contoured. The internal 

 markings — striae — show along the margins for several days. On the 

 upper part of the slant the bacteria are in a very thin layer, becoming 

 thicker toward the lower part and with white sediment in the condensa- 

 tion water in the V. 



Gelatin plates. — ( + 10 peptone-beef gelatin). In 48 hours at 20° C. 

 the well-isolated colonies are iK mm. in diameter. The liquefied pits 

 are shallow, saucer-shaped depressions, circular and with definite, entire 

 margins. The liquid gelatin is slightly clouded, and the bacteria are 

 mostly in a tiny white mass at the center of the depression. In 4 days 

 well-isolated colonies are from 6 to 8 mm. in diameter. Thickly sown 

 plates are ehtirely liquefied in 48 hours at 20°, with the colonies as tiny 

 white masses floating in the slightly cloudy and slightly greened liquid. 



Gelatin stabs. — Cultures kept at 17° to 18° C. have small liquefied pits 

 on the surface in two days. The stab does not develop more than a trace 

 of growth. The liquefaction becomes stratiform and proceeds slowly, 

 being complete only after from five to seven weeks. At a temperature 

 of 20° the liquefaction is more rapid, and the stab develops into a wide 

 pocket containing numerous small white masses. At both temperatures 

 the gelatin is greened. 



Beef-peptone bouillon. — At room temperatures (20° to 27° C.) a 

 slight clouding occurs at the surface in from 6 to 7 hours. The growth 

 increases, always being best at the surface, forming clouds and pseudo- 

 zoogloeae. In some cases a delicate pellicle forms. Rims are often 

 present, thin, white, easily disintegrating. Growth is never very heavy 

 in -fio to 4- 14 beef bouillon. The slight sediment is white, fine- 

 grained to flocculent, and is readily dissolved into clouds on shaking. 

 Medium yellowish green ("Chalcedony Yellow" or "Chartreuse Yellow"). 

 Beef bouillon over chloroform. — Growth unrestrained. 



' The colors mentioned in this paper are given according to Ridgway (lilDGWAY, Robert. 

 STANDARDS AND COLOR NOMENCLATURE, 43. P-. Si ^ol- pl- Washington, D. C, 1912) 



