396 



BACTERIAL DISEASES OF PLANTS 



of the parasite, which, on account of the reigning confusion 

 respecting the nature of Bacillus oleae (Arch.) Trevisan, was 

 given a new name Bacterium savastanoi, in honor of Luigi 

 Savastano (Fig. 308), who first proved the oHve tubercle to be a 

 bacterial disease. With these introductory remarks we may 

 proceed to a description of the organism. 





X-. 



Fig. 304. — Cross-section of an olive petiole showing the brown channel of 

 bacterial infection at A'. Cut between a primary stem-tubercle (due to needle- 

 pricks introducing Bacterium savastanoi) and a deep (unruptured) secondary 

 tubercle on the leaf. See next figure. 



The olive tubercle is due to Bacteriurn savastanoi EFS. 

 This is a slow-growing, white, non-sporiferous, motile, 1 to 4 

 polar-flagellate (Fig. 309), aerobic, non-liquefying (gelatin 

 and Loffler's solidified blood serum), non-gas-forming (see 

 Petri's statement), non-nitrate-reducing, sunlight-sensitive, heat- 

 sensitive, acid-forming (with grape sugar and galactose), 



