BACTERIAL DISEASE OF TOBACCO. 45] 
Table VILI.—Zobacco Plants (Tamworth ). 
Plate I (No. 1) Plate I (No. 4) 
Sugars —Glucose | no change no change 
Mannite of ” 
Dulcite Ae Ye 
Lactose a 43 
Saccharose ss Br 
Milk digestion digestion 
Litmus milk ‘complete digestion complete digestion 
Gelatine liquefaction liquefaction 
Agar plate dirty white, dendritic dirty white, circular moist 
In examining these tables we find that the following 
colonies give reactions very closely resembling those 
ascribed to Bact. solanacearum :— 
Table VIII, Plate I, No. 1 this organism differs only from 
” 3 ” 35 B. solanacearum in the 
meets «55 TH, ., f liquefaction of gelatine. 
this organism differs only from 
Vv 1 B, solanacearum in giving 
a a a Meher ( acid on glucose and green 
fluorescence on gelatine. 
From the various diseased tobacco plants examined, pure 
cultures of bacteria have been obtained almost without 
exception. The colonies on the poured plates were moist, 
dirty white in colour, and either circular or dendritic; this 
difference in shape of the colonies seems to be of not much 
importance, since the morphology and the reactions agree 
in any comparative series of the two. The organisms are 
motile, gram negative short rods. With three exceptions 
all gave acid on glucose, and as regards milk, sixteen out 
of the twenty cultures examined caused it to clot. 
I am indebted to my assistant Mr. W. A. Birmingham for 
much careful work in connection with the organisms 
isolated and examined. 
Summary. 
1. Peronospora hyoscyami is the cause of a disease 
which gives rise to serious loss in tobacco seed beds. 
