FOWL CHOLERA 83 



but not before 48 hours, a thin greyish-yellow line of 

 growth which gradually broadens during the next days, 

 its outline rounded and knobbed, but even after a 

 week to a fortnight does not reach in breadth more 

 than a few millimetres. In stab culture the stab 

 becomes marked as a line composed of minute dots, 

 brownish in transmitted light, whitish-yellow in re- 

 flected light ; at the upper free end of the gelatine 

 is a small rounded plate of growth slightly raised, 

 with irregular outline, and, after a week or ten days, 

 measuring a few millimetres. The gelatine is never 

 liquefied. Alkaline beef-broth peptone incubated at 

 35-37° C. becomes slightly turbid by the growth of the 

 microbe in 24 hours ; the turbidity increases during 

 the next days, but, even when the maximum develop- 

 ment has been reached, is never very pronounced. 

 There is then present a small amount of a greyish- 

 white powdery precipitate. On the surface of Agar 

 the growth forms a thin, translucent, grey film ; on 

 potato sterilised in the steamer, and then kept at 

 35-37° C., the growth is slow and remains fairly 

 limited to the region of inoculation, forming a whitish 

 or light brown film spreading slowly in breadth. 



As has been mentioned above, a drop of a broth 

 culture 24-48 hours old, or a drop or two of a salt 

 mixture of the growth taken from a fairly recent 

 gelatine or Agar culture, invariably produces fatal 



