608 A FISH DISEASE PROM GEORGE'S RIVER, 



appears at the top. The liquefied medium is turbid, and there is 

 a white deposit but no film. In 48 hours the medium is almost 

 completely liquefied, the fluid is turbid, and there is a slight film. 

 After a time (7 days) a turbidity extends from the surface to 

 about 05 cm. downwards, the lower portion of the liquefied 

 medium is clear, and there is a white granular deposit; no film is 

 apparent. 



Glucose-gelatine or lactose-gelatine. — No gas is produced in 

 either of these media. 



Agar plate. — The surface colonies are circular, translucent white, 

 raised, and moist glistening. When magnified they are seen to 

 be circular, finely granular, with isolated coarse granules in the 

 centre; the margin is homogeneous and the edge smooth. The 

 deep colonies when magnified are seen to be yellowish brown, 

 coarsely granular, and irregularly shaped, an arrow-head pattern 

 being most usually seen. 



Agar slope. — At 22° the growth is translucent white and raised, 

 with a slightly lobed or straight margin and smooth edge. It is 

 spread out and irregular at the base when in contact with the 

 condensed water. The latter is turbid and contains a sediment. 

 At 37° the organism refuses to grow unless a considerable quantity 

 of material is used for sowing. The growth is, however, never 

 so luxuriant as at 22°. 



Bouillon. — The medium becomes turbid, especially near the 

 surface, upon which a slight film forms; there is a precipitate. 

 The turbidity persists, and at the end of seven days a slight indol 

 reaction can be obtained. 



Anaerobic culture. — The organism grows in bouillon when placed 

 in Buchner's tubes, but not so freely as in the presence of air. 



Nitrate-bouillon. — The nitrate is strongly reduced in I days to 

 nitrite. 



Litmus-milk. — The casein partly dissolves and partly precipi- 

 tates, while the litmus is first reddened . and finally (7 days) 

 bleached. 



Potato. — There is a flat growth barely perceptible, being just 

 sufficient to obscure the glistening surface of the medium. 





