YELLOW DISEASE OF HYACINTHS. 345 



show many long slender chains and also filaments 50 to 150 /x long in which no septa are 

 visible (fig. 141). The organism is motile, and a polar flagellum has been demonstrated 

 (fig. 142). Involution forms occur. Rods from young cultures stain readily; those from 

 old cultures and from the overcrowded vessels take stains less freely. Wakker recom- 

 mended Bismark brown (phenylene brown). The writer has used Ziehl's carbol fuchsin, 

 and Gram's stain with amyl alcohol. 



The purest color of the organism is bright yellow (gamboge, chrome, canary, or pale 

 cadmium). The color is best developed in the plant and near the surface of fluid and solid 

 culture media. When the air-supply is scanty the color is pale yellow. Duller and paler 

 yellows occur also in certain media when oxygen is abundant, e. g; in potato-broths and 

 acid beef-broths (not alkaline ones). In peptonized beef-bouillon, neutralized by sodium 

 hydroxide, the color was canary yellow. The color was also bright in nutrient gelatin 

 containing malic acid. This color appears to be a lipoehrome compound, as it is associated 

 with a fat. It is soluble in acetone, glycerin, a water solution of ammonium carbonate, or 

 hydrogen peroxide, and slowlyalso in strongammonia water, glacial acetic acid, ethyl acetate, 

 ethyl alcohol, and methyl alcohol. The pigment can not be extracted with petroleum ether. 

 The acetone extract, which also removes the fat, yields a blue-green or purplish reaction 



( N\ 





Fig. 139.f Fig. I40.{ Fig. 142 



'/too m m 



Fig. 138.' Fig. 14l. 



with concentrated sulphuric acid, and is readily destroyed by light. The yellow pigment 

 is also bleached by reducing agents, the color returning on their removal (for further details 

 consult Bulletin 28). The brown stain appears to be similar to that developed by Bad. 

 campestre, but is less pronounced. It is soluble in water, and free oxygen appears to be 

 necessary for its formation. It was best developed in hyacinth-broth, potato-broth with 

 peptone, and on steamed turnips, radishes, and yellow banana rinds standing in distilled 

 water. Sienna and burnt umber were the darkest shades observed (old cultures on radish 

 and turnip). It was not observed in beef-broth, nutrient agar, starch-jelly or nutrient 

 gelatin. It occurs in the plant, so far as observed, only in the vascular bundles of the leaves, 

 and is not pronounced. In nutrient media it is best observed in old cultures. 



Bad. hyacinthi is not sensitive to dry air. Wakker made this discovery and the writer 

 has confirmed it. Thirteen cover slips, which were spread by the writer with a thin layer 

 of bacteria from a young potato-culture and dried for 9 days, each infected culture media 

 when thrown into it. Two of the same covers dried for 47 days at room-temperatures also 

 yielded pure cultures when thrown into beef-bouillon. In another experiment 17 out of 18 

 similar covers infected beef-bouillon after being dry for 49 days (compare in this particular 

 with B. tracheiphilus and B. carotovorus) . 



*Fig. 138. A detail of Bad, hyacinthi from fig. 137 at X. Slide 502 B-A7. 



fFic 139. Rods of Bait, hyacinthi. x 4000. After Wakker, Verslag, 1883, pi. I, fig. 1. 



|Fig. 140. Rods of Bad. hyacinthi: a, directly from bulb; b, from a young beef-bouillon culture, x 1000. 



Fig. 141. Filaments of Bacterium hyacinthi from a culture on cane-sugar agar.segments not visible. Stainedby 

 van Ermengem's nitrate of silver method, x 1000. 



||Fig. 142. Rods of Bacterium hyacinthi, showing flagellum: a, stained by V. A. Moore's modification of Loeffier's 

 method; b, stained by Alfred Fischer's method, x 1000. 



