THE OLIVE tubercle: MORPHOLOGY 407 



club-shaped and branched bacterial forms found in gastric diver- 

 ticula of the larvae of the olive fly (Dacus oleae), and calls them 

 Bacterium savastanoi. 



Cultural Characters. — Study and describe the behavior of this 

 organism on thin-sown agar plates; in agar stabs and streaks. 

 Look for ring-formed colonies in peptone gelatin plates contain- 



FiG. 313. — Surface colony of Bacterium savastanoi on +10 peptone-beef gelatin 

 containing 1 per cent grape sugar. Time, several weeks; temperature 18°C. 

 Photographed to show lobes; and the ringed appearance, first mentioned by 

 Petri. X 7. 



ing 1 per cent dextrose (Petri). Make very thin-sown +10 

 beef-peptone-gelatin plates, keep at 20° to 22°C. and draw the 

 peculiar marginal frill. Observe the same marginal behavior 

 on gelatin streaks. Savastano likened this growth on gelatin 

 to a leaf. Study development of the pellicle in tubes of peptone 

 water. Observe the formation of crystals in Cohn's solution, 

 e.g., in an undisturbed small flask. Collect them in quantity 



