636 
Journal of Agricultural Research 
Vol. XI, No. 12 
merous trials show the thermal death point of 2-hour cultures made from 
48-hour cultures to be apparently about 50°. In the case of old cul¬ 
tures growth has been obtained and pathogenicity of organism proved 
after a 10-minute exposure to 55V indicating the development of a 
slightly more resistant type of cell under these conditions. 
DESICCATION 
The organism is highly resistant to drying as it occurs normally in the 
host tissues, since, as previously explained, it has been isolated from dried 
herbarium specimens of leaves 8 months old and it may live on the 
seed at least two years. It also survives long on culture media. When 
dried on sterile cover glasses it seems more sensitive. Thus, a young 
well-clouded bouillon culture was diluted with equal parts of sterile 
water and a full 2-mm. loop transferred to each of a series of sterile 
cover glasses and these dried in a sterile chamber. When tested by 
plunging these in broth at intervals, it was found that most perished 
within 24 hours, and all within two days. 
susceptibility to mercuric chlorid 
Various tests have shown the organism to be very sensitive to mercuric 
chlorid. 
technical description 
On the basis of the foregoing studies the parasite in briefly charac¬ 
terized as follows: 
Bacterium translucens, n. sp. 1 * 2 
Cylindrical rods rounded at ends, solitary or in pairs; individual rods 0.5 to 0.8 by 
1 to 2.5 n, motile by a single polar flagellum; aerobic, no spores. 
Superficial colonies in peptone-beef agar plates round, smooth, shining, amorphous 
except for inconspicuous somewhat irregular concentric striations within, wax-yel¬ 
low tinged with old-gold; margin entire. 
Liquefies gelatin slowly; produces slight acidity in milk; digests casein; nitrates 
not reduced; acid produced in cultures with various sugars. No gas produced. 
Gram-negative. Group number 211.2222532. 
Pathogenic in leaves of Hordeum vulgare , H, distichum, H. hexastichum, forming 
translucent elliptical to striaform lesions. 
Type locality: Madison, Wis., on Hordeum vulgare. 
Distribution: Northern Mississippi Valley and westward to Pacific coast. 
1 According to Migtila’s classification, the combination would be Pseudomonas translucens , n. sp. 
s Bacterium translucens, sp. nov., aerobium, asporum; coloniis cum striis inconspicuis intends ali- 
quid irregularibus concentricisque; baculis cylindricis apicibus rotundatis, solitariis vel binis; baculis 
singulis 0.5—0.8X1.0— 2.5 ft* flagello uno polare mobilibus. 
Coloniae superficiales in agar-agar rotundae, leves, nitentes, melleae. Liquefacit gelatinam lente. Lac 
sterile addum facit; casein segregat. Nitrum non redigit. Culturae in mediis cum saccharo sacchari, 
saccharo uvae, saccharo lactis acidae hunt. Gas non fadtur. Methodo Grami non coloratur. 
Habitat in foliis vivis Hordei vulgaris, H. distichi, H. hexastichi in lineis vel maculis translucentibus. 
Madison, Wisconsin. Amer. bor. 
