428 A Tomato Canker 



1 : 25 ; phenol 1 : 500 ; mercuric chloride 1 : 500 and formalin ] : 200. It is 

 extraordinarily resistant to copper sulphate, the lethal coefficient for 

 Bacillus mangiferae being about 1:400. The inhibition coefficient was 

 not determined very exactly; the bacterium grows in a bouillon con- 

 taining 1 : 1000 copper sulphate, but was inhibited by 1 : 800; the same 

 result was obtained with formalin. The organism grows in bouillon con- 

 taining phenol 1: 800 but not in 1: 600; similarly it grows in mercuric 

 chloride 1 : 3000 but not in 1 : 2500. 



Desiccation. A number of sterile cover slips were covered with a 

 film of the organism and placed in sterile ventilated petri-dishes in a 

 desiccator; one of these was removed each day and dropped into a tube 

 of nutrient bouillon. No growth was obtained from cover slips which 

 had been exposed to desiccation for more than ten days. 



Nomenclature. 



The name Bacterium vesicatorium n. sp. is suggested for this organism, 

 which has apparently not previously been described: its chief characters 

 are as follows: 



Bacterium vesicatorium n. sp. A parasite of the tomato plant, causing 

 spots on leaves and stems and raised blisters or cankers in the fruit. 

 A motile rod averaging 1-1*5 x -6--7/x, with rounded ends and a single 

 polar flagellum, occurring singly, in pairs, or in short chains. On nutrient 

 agar colonies appear in 48 hours at 30° C. and are finally circular, about 

 5 mm. diameter, semi-translucent, Naples yellow in colour. On potato 

 produces a copious yellow, spreading growth, butyrous or rather viscid 

 in consistency. Liquefies gelatine and blood serum; no growth in 

 Uschinsky's and Cohn's solutions: grows slowly but well in Fermi's 

 solution. In milk there is a separation of whey, and casein becomes 

 slowly peptonised. Is a fairly active proteolytic agent, destroys starch 

 very slowly. There is no gas formation in sugar bouillon ; there is a slight 

 increase in acidity but bouillon ultimately becomes more alkaline. No 

 definite evidence of nitrate reduction was obtained; no indol or phenol 

 is produced in bouillon or Dunham's solution. The organism is strictly 

 aerobic ; grows through a wide range of temperature from 5° C. to 40° C. ; 

 the optimum temperature for growth is about 30° C. ; thermal death 

 point 56° C. Does not grow in alkaline media, but tolerates a fair amount 

 of acid; growth inhibited by 4 per cent, sodium chloride. Group number 

 211, 2332523. 



Two other yellow organisms have been described as causing diseases 



