YELLOW DISEASE OF HYACINTHS. 345 
show many long slender chains and also filaments 50 to 150 uw 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, ¢. 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 lipochrome compound, as it is associated 
with a fat. It is soluble in acetone, glycerin, a water solution of ammonium carbonate, or 
hydrogen peroxide, and slowly also in strong ammonia water, glacial aceticacid, ethylacetate, 
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 
vei (Ls 
fe \ 
VQ bo ee 
/ 
Fig. 139.+ Fig. 140.t Fig. 142.|| 
Fig. 141.§ 
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 Bact. 
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. 
Bact. 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). 
*Fic. 138.—A detail of Bact, hyacinthi from fig. 137 at X. Slide 502 B—A7. 
tFic. 139.—Rods of Bact. hyacinthi. x 4000. After Wakker, Verslag, 1883, pl. I, fig. 1. 
tFic. 140.—Rods of Bact. hyacinthi: a, directly from bulb; 6, from a young beef-bouillon culture. x 1000. 
§Fic. 141.—Filaments of Bacterium hyacinthi from a culture on cane-sugar agar, segments not visible. Stained by 
van Ermengem’s nitrate of silver method. x 1000. ; 
\|Fic. 142.—Rods of Bacterium hyacinthi, showing flagellum: a, stained by V. A. Moore’s modification of Loeffler’s 
method; 5, stained by Alfred Fischer’s method. x 1000. 
