8 QUATERCENTENARY STUDIES IN PATHOLOGY 



Bacillus of Disease "A." 



The examination of the peritoneal liquid of certain sheep said to 

 have died of Braxy showed the presence, not of the bacilli of Braxy or 

 of Louping-ill, but of bacilli which have been temporarily classified by 

 Professor Hamilton into two groups— " A" and "B" (cf. Report, Pt. II., 



p. 259). 



The bacillus having been isolated by heating in glucose-bouillon, 

 growth was obtained after 24 hours' incubation, with evolution of gas 

 and turbidity of the medium. In three days, the medium became 

 clear, and of an acid reaction, with a greyish-white deposit at the bottom 

 of the tube. This deposit was, in great part, composed of coarse, 

 straight rods, with rounded ends, varying in length from 2*8 to 6/x, and 

 broad in proportion to their length. Movement, if any, was very slight. 

 They stained readily with fuchsin and methylene blue, and gave a positive 

 reaction to Gram's process. Spores were not developed till the second 

 day of incubation, when a single, small, rounded, refractile body was 

 present towards one end of the rod. Cilia could not be demonstrated. 



Growth on Gelatine. 



Streak cultures, under aerobic conditions, showed no growth, even 

 after weeks of incubation. 



Stab cultures, grown under oil, after 7-10 days' incubation, began to 

 show slight liquefaction of the gelatine in the form of a cone at the top 

 of the tube, but, deeper down, tended to spread laterally. The quantity 

 of growth in each case was very slight, amounting to little more than a 

 faint yellow film on the sides of the cavity. Lateral projections, as in 

 the case of Braxy and Louping-ill, were not observed. 



Growth on Agar. 



Streak cultures showed no change when incubated in the presence of 

 oxygen, but, under hydrogen, after two days, a narrow line of growth 

 had developed, made up of single, rounded, faintly greyish-tinged 

 colonies. On the fifth day it assumed the form of a band, about \ in. 

 broad, whose centre was homogeneous, but whose border was crenated 

 from the presence of rounded colonies. The growth was very slightly 



(408) 



