72 A Bacterial Sjjot of Citrus 



Carrot. The water in the bulb of the Roux' tube is distinctly 

 clouded, on the carrot there is a plentiful, colourless wet-looldng, shining 

 growth spreading over the medium. 



Turnip. Growth is much less abundant than on carrot, it is not 

 quite colourless but has a yellowish tinge. 



Beet. Here the growth is very similar to that on carrot but is 

 distinctly yellow, and there is a yellowish ring at' the surface of the 

 liquid in the bulb of the Roux tube. 



Orange and lemon rind steamed show after three days gUstening, 

 dirty yello\\ish masses of slightly viscid bacilh raised above the surface 

 of the rind. 



Nutrient bouillon (+ 15 Fuller), Nutrient broth clouds in six 

 hours at temperatures from 25° to 35° C, and in 24 hours there is a 

 distinct suggestion of pelhcle formation. The pelHcle is thin and falls 

 to the bottom of the tube if the latter is shaken shghtly. Three months 

 old cultures are almost clear; there is a small amount of dried up 

 growth on the tube where the surface of the medium originally was 

 and a considerable amount of deposit. The rods in the deposit are 

 hving and multiply readily when transferred to fi-esh tubes of broth. 



Pellicle formation takes place most readily on broth with an acid 

 reaction, on alkahne broth httle or no pelhcle is formed. After stand- 

 ing for some days flasks of acid broth showed a thin pelhcle in which 

 were suspended numerous more opaque portions which are shining, 

 yellowish and rather greasy looking. In some hghts the pelhcle is 

 distinctly iridescent. 



The ring above the hquid does not become tough or mucilaginous, 

 and the pelhcle is flocculent. 



Sugar bouillons. The growth in dextrose broth is not particularly 

 good ; a heavier clouding was obtained in broth containing maltose, 

 lactose and galactose, and the best growth of all in 2 per cent, laevulose 

 broth. 



Litmus milk. In milk the bacillus grows comparatively slowly; 

 no change could be observed for seven days, after that period the miUc 

 became shghtly more acid in reaction and the htmus was then gradually 

 reduced. After 10 days at 35° C. the casein coagulated and there w^as 

 a gradual extrusion of whey. The whey was not abundant, almost 

 clear, and yellowish in colour, a sediment of yellow bacteria gradually 

 accumulated on the surface of the coagulum : the latter did not 

 become peptonised. 



MilJc serum, fdtered through a porcelain candle, proved to be 



I 



