Apr. a, 1917 
A New Bacterial Citrus Disease 
3 
sistently; and reisolations from these inoculations gave the same typical 
colonies. The organism has been repeatedly inoculated and reisolated 
since that time, and has also been repeatedly isolated from material 
from different regions of the State, both from the fresh black lesions and 
the reddish blister-like scabs found in summer. Both types of lesions, 
the black watery effect on the leaves and twigs and the reddish scabs, 
have been produced from artificial inoculations with pure cultures. In 
the inoculation work young lemon and navel-orange trees have been 
used and kept in the greenhouse at temperatures of 20° to 25 0 C. 
According to the methods in use at present by bacteriologists, the 
organism is a distinct species; and, so far as is known, has never been 
described in the literature on the subject. Owing to the withering or 
drying up of the leaves of Citrus trees following the attacks of this organ¬ 
ism the specific name “ citrarefaciens” is suggested—a compound of the 
two words “Citrus” and “arefacio.” The brief Latin diagnosis is as 
follows: 
Bacterium citrarefaciens, sp. nov. 
Baculis cylindricis, apicibus rotundatis, solitariis aut interdum geminis, 1.2— 3X0.4 
—0,9 jli, vulgo 0.6X 1.8 fjtf motilibus, flagellis 1-4, uni-aut-bipolaribus; methodo Grami 
non coloratis; cum acidibus decoloratis; sporis capsulisque nondum visis; zoogloeis 
defectis; statubus involutis, longe-filamentosis, massulas protoplasmaticas densiore 
tinetas complectentibus, coloniis in agar-agar orbicularibus, convexis, nitentibus, 
margaritaceo pallidis, colorem fluorescenti-viridem in medium alibile efficientibus; 
gelatinis primum celeriter deinde lente liquefacientibus; casein segregantibus; lactem 
litmus lente decolorantibus; in mediis saccharatis neque gas neque acidum evolvatis; 
nitrum non reducentibus; indol ammoniamque moderate producentibus; aerobicis sed 
in presentia sacchari, sacchari uvae, aut sacchari hordei facultative anaerobicis. In 
textis vivis arborum citrinorum, laesiones foliorum cauliumque juvenorum, primum 
nigras deinde in mensibus siccis aestivalibus rubras scabrosasque efficiens. 
HISTOLOGY 
Affected areas of young leaves were fixed, embedded, sectioned, and 
stained. It was found that the organism in tissues could be stained best 
with Mallory's chlorid-of-iron hematoxylin, as described by Mallory and 
Wright. 1 Impregnation with gold chlorid, according to Lee, 2 also gave 
good results, the impregnation being carried on after the sections had 
been fixed on the slides, however, instead of in toto, as described by Lee. 
Masses of bacteria could be observed throughout the parenchyma of 
the leaf, both in the cells and in the intercellular spaces. In many lesions 
# all cell structures had disappeared, the areas being occupied by masses 
of the organisms (PI. 1, C). The disease is not to be considered as an 
invasion of the vascular bundles, but rather as an attack upon the 
parenchyma. 
1 Mallory, F. B., and Wright, J, H. Pathological Technique . . . ed. 3, 469 p., 138 fig. Philadelphia, 
1904- 
2 Tee, A. B. Microtomist’s Vade-Mecum . . . ed. 7, 526 p., illus. Philadelphia, 1913. 
