470 
Journal of Agricultural Research 
Vol. V, No. ii 
MORPHOLOGY AND PHYSIOLOGY OF BACTERIUM LACHRYMANS 
MORPHOLOGICAL CHARACTERS 
As it occurs in the plant and also on media the organism causing the 
disease is a short rod with rounded ends, single or in pairs (Pl. XLVIII, 
fig. 2 and 3), o.8ju wide by 1 to 2 fx long. On culture media it occurs 
singly or in pairs with a very decided constriction, and occasionally (in 
salted bouillons) in chains of as many as 12 or more individuals (Pl. 
XLVIII, fig. 1). No spores have been seen. Capsules are formed on 
agar (Pl. XLVIII, fig. 2), and in milk (Ribbert's stain). It is motile 
by means of 1 to 5 polar flagella (Pl. XLVIII, fig. 3). It is Gram¬ 
negative and is not acid-fast. 
EFFECT OF DESICCATION 
When drops from 24-hour peptone bouillon were placed on sterile 
covers in sterile Petri dishes and kept in the dark at room temperature, 
the organism was not killed by 21 days' drying, but it gave no growth 
when covers were dropped into suitable bouillon after 6 weeks' drying. 
TEMPERATURE RELATIONS 
The best growth was obtained at 25 0 to 27 0 C. There was no growth 
at 36°, though bouillon was weakly clouded at 35 0 C. Slow growth 
occurred at i° in bouillon cultures (two weeks' time). 
SENSITIVENESS TO SUNLIGHT 
Agar plates, thin-sown, from an 8-day bouillon culture were exposed, 
bottom up on ice, to sunlight in June for 5, 10, and 15 minutes, one-half 
of each plate being protected from the light by several thicknesses of 
black paper. After five days' incubation numerous colonies appeared, 
and no difference was observed between the insolated and covered side 
on any of the six plates (but the colonies were not counted). Another 
test was made in September, 1915, with the following results: 
The fluid used for inoculation consisted of one 3-mm. loop from a 
24-hour bouillon culture into 10 c. c.. of bouillon. Five plates were 
inoculated, each with one 2-mm. loop from this suspension. Five other 
plates were inoculated, each with one needle from this suspension. One 
plate from each lot was then half covered and exposed bottom up on ice 
for 5, 15, 30, 45, and 60 minutes, respectively. Result: All were killed 
by 45 and 60 minutes' exposure; three-fourths were killed by 30 minutes' 
exposure; one-third were killed by 15 minutes’ exposure; and one-fourth 
were killed by 5 minutes' exposure. 
When these results were obtained with the 24-hour bouillon, the experi¬ 
ment with the 8-day bouillon was repeated. Four agar plates were poured, 
one-half of each being exposed bottom up on ice, two for 15 minutes and 
two for 30 minutes, the sky being clear and the sun bright (October 12). 
