28 Bacterial Disease of the Mango 



the surface of the latter was covered with a yellow wrinkled growth. 

 The colour was deeper than on most media, varying from light orange 

 yellow to deep chrome (III 17, — Y, d — b). 



Carrot. This was not a favourable medium, a thin spreading growth 

 covered the moist parts of the cylinder. 



Nutrient broth (+15 Fuller). The bacillus grows very vigorously in 

 nutrient broth ; at 30° C. a slight clouding is visible in 6 — 8 hours ; 

 after 24 hours a ring begins to form above the surface of the liquid, and 

 in 48 hours it is well formed and yellowish in colour. A thin pellicle 

 forms on the surface of the broth, and this sinks to the bottom if the 

 tube is slightly shaken and forms a sediment. After three months the 

 broth becomes almost clear, the ring has dried on the sides of the tube, 

 and all of the pellicle fallen to the bottom. 



The ring formed above the surface of the broth is very tough and 

 slimy; it is almost impossible to break it with a platinum needle. 

 Cultures in nutrient broth had no noticeable odour. 



In broth containing 2 % dextrose, similar results are obtained, but 

 the clouding is heavier ; in a medium containing 6 % glycerine, on the 

 other hand, there is a much less copious growth. 



Dunham's solution. The bacillus does not grow well in peptone 

 water, but this medium becomes slightly clouded in 48 hours. There 

 is no pellicle and no sediment. 



Litmus milk. The tubes when inoculated were deep lavender in 

 colour (XXXVI) and the controls did not change during the time that 

 they were kept under observation. 



The organism grows very slowly in milk tubes, and it was not until 

 the tenth day that there was any decided change. After 12 days at 

 25° C. the colour was pale lilac (XXXVII) ; on the 16th day it was 

 flesh pink (XIII), and this change of colour was accompanied by a 

 curd-like coagulation of the casein with a separation of whey. 



At 30° C. a similar coagulation took place after the same lapse of 

 time, but the reaction was not so acid, the colour being pale cinnamon 

 pink (XXIX). At these two temperatures no further change of colour 

 took place, nor was there any solution of the curd ; but after 25 days 

 the colour was completely reduced in all the tubes. 



At 37° C. the medium did not turn pink, but after 12 days the 

 colour was completely reduced. The casein coagulated but there was 

 no extrusion of whey. The curd was then gradually dissolved, and 

 after 27 days all that remained was a clear yellow fluid with a slight 

 bacterial sediment at the bottom of the tube. 



