Apr. 2, 1917 
A New Bacterial Citrus Disease 
5 
Potato cylinders. —Growth on potato cylinders is moderate, filiform, becoming 
echinulate, and spreading with age; at first convex, becoming flattened, glistening, 
smooth, cream-buff in color, the medium itself being slowly browned until it becomes 
avellaneous. There is a slightly saline odor from the cultured cylinders. At the end 
of the fifteenth day starch reduction was tested by means of iodin in a potassium- 
iodid solution. Uninoculated cylinders gave the typical blue starch reaction, but 
cultured media gave the port-wine color indicative of the formation of amylodextrin 
or still lower reduction products. 
Milk. —The casein in inoculated milk coagulates slowly, leaving at the surface a 
clear liquid which has a fluorescent-green color. Peptonization of the coagulum then 
takes place slowly, being complete in 25 to 30 days. The consistency of the medium 
is unchanged. 
Litmus milk. —Growth in litmus milk is distinctive; the coagulated portion remains 
the original lavender color, but the cleared portion becomes a deep glaucous gray. 
Beneath the upper stratum a layer of light violet-gray appears, while a sediment of pale 
olive-buff collects at the bottom of the tubes. As the coagulum is slowly peptonized, 
the sediment and the deep glaucous-gray layer increase in depth; and when the 
coagulum has entirely disappeared the litmus becomes rapidly reduced. At the end 
of 25 days the tubes have lost all the litmus color, and are similar in color to peptone- 
beef bouillon. The blue has sometimes been restored by shaking; but at no stage was 
there any formation of acid. 
Us chins ky ’s solution. —Growth in Uschinsky’s solution is heavy, slightly turbid, 
with no surface growth; on the fourth day the medium becomes viridine-green. In 
old cultures there is a very slight sediment, which is slightly viscid. 
Fermi’s solution. —Growth is scanty and uniform, with no surface growth; there 
is a slight green color similar to that produced in Uschinsky’s solution. 
Cohn’s solution. —Growth in this medium is scanty, forming only a thin, uniform, 
scarcely visible clouding. 
Starch jelly. —Starch jelly was made by adding 1 gm. of potato starch to 10 c. c. 
of Uschinsky's solution. Growth was moderate; the medium was turned to a 
fluorescent-green color. On adding an iodin solution to the medium a reddish-brown 
color w T as first formed, which on standing several minutes entirely disappeared, 
indicating the formation of achroodextrin, or even lower reduction products. There 
is a positive diastasic action. 
Toleration or sodium chlorid.-— Tubes of peptone-beef bouillon acidified to +10 
and containing 1.5, 2.5, 3, 4, and 5 per cent of pure sodium chlorid were inoculated 
from 2-day-old agar slant cultures. Growth was moderate in the 1.5 and 2.5 per cent 
sodium-chlorid cultures, and was scanty in the 3 per cent cultures. In the cultures 
containing 4 per cent of sodium chlorid a clouding was formed, scarcely apparent to 
the eye, while in the 5 per cent cultures growth was entirely inhibited. 
Bouillon over chloroform. —Growth is unrestrained in + 10 peptone-beef- 
bouillon tubes to which 2 c. c. of chloroform have been added. 
Fermentation tubes. —The tests for gas and acid production were made in fer¬ 
mentation tubes containing neutral peptone-beef-litmus bouillon to which was added 
2 per cent of the compound to be tested; these were dextrose, saccharose, maltose, man- 
nite, and glycerin. Growth occurred most abundantly in the tubes containing dextrose 
and saccharose, but growth was abundant in all the sugar media. A reduction of the 
litmus took place in all the media, especially rapid in the glucose bouillon, the liquid 
finally becoming the color of standard peptone-beef bouillon. Neither gas nor acid 
was formed in the presence of any of the sugars after 15 days. In the presence of 
dextrose, saccharose, and maltose, clouding could be observed in the closed arms of 
the fermentation tubes; but in those tubes containing the bouillon with glycerin, 
mannite, and lactose, growth took place only in the open chambers. 
Ammonia production.— Peptone-beef-bouillon cultures tested at the end of the 
tenth day, using Nessler’s reagent, gave a strong reaction for the presence of ammonia. 
