THE OLIVE tubercle: CAUSE 



399 



formed in litmus milk either with or without cream, nor is 

 the casein of milk precipitated. The organism has only a very 

 slight action on olive oil (Petri, Smith and Brown). Cane- 

 sugar is inverted (Petri, Smith and Brown) There is only a 

 slight indol reaction. The organism stains readily with Ziehl's 

 carbol fuchsin, but not by Gram. It is not acid-fast. It 

 grows readily and for a long time in Cohn's solution (very often 

 in the form of long rods, sometimes in chains) without fluores- 

 cence (Petri says with it) and with the formation of numerous 

 crystals of ammonium magnesium phosphate. These crystals 



^5,,,j*^^,,p,.*S^IB&'^^ 



iH 





Fig. 307. — Section through an olive leaf showing structure of a young tubercle 

 developing from the lower surface. Result of a needle-prick inoculation. Palisade 

 tissue undisturbed. 



become conspicuous in the thin pellicle if the tubes or flasks 

 are left undisturbed for a few days. In Cohn's solution with 

 1 per cent dextrose, rods in clumped masses occur. In Us- 

 chinsky's solution the bacteria are motile and elongated. 

 Repeated in 1919: thinly clouded on 4th day; best growth in 

 top 3^2 cm. ; on 8th day a thin white pellicle, no fluorescence, 

 very thinly clouded; motile, short filaments were present; 

 after 6 weeks still clouded, not fluorescent. The organism 

 grows from 1°C. or below, to 35°C., or a little above. It will 

 not grow in bouillon at 38.5°C. and is always killed in +15 pep- 

 tone-beef bouillon by 10 minutes exposure in the water-bath at 



