488 " Blackleg'' of the Potato 



Staining. The organism stains well with the usual bacteriological 

 stains. It exhibits no polar or other characteristic granules. It does 

 not stain by Gram's method. Spores have not been observed. 



II. Cultural Characters. 



Stab Culture in Bouillon-gelatine. In acid gelatine (titrating + 10 of 

 Fuller's scale), after 24 hrs. at 20° C, growth was visible to the bottom 

 of the tube and liquefaction had commenced at the upper part of the 

 stab. After 48 hrs. liquefaction was "infundibuliform" and had spread 

 to about 8 mm. diameter at the surface. A granular deposit formed 

 in the liquid gelatine and gradually sank to the bottom. The reaction 

 of the liquid was strongly alkaline to litmus. In alkaline gelatine 

 {— 1-5) growth was similar but rather more rapid. 



Stab Culture in Bouillon-agar . Growth was granular and uniform 

 throughout the length of the tube. The organism is obviously a faculta- 

 tive anaerobe. No difference in growth could be observed on media 

 of acid or alkaline reaction. 



Streak Culture on Bouillon-agar. After 24 hrs. at 20° C. the streak 

 was 1-5 to 2mm. wide with smooth margin; dirty white by reflected 

 light; raised; "wet-shining." When collected in a mass on a platinum 

 wire a faint yellow colour was perceptible. 



Plate Culture on Bouillon-gelatine. After 48 hrs. at 20° C. the 

 colonies had made their appearance and those on the surface had 

 liquefied the gelatine ; liquefaction basin-shaped ; bluish-grey turbidity ; 

 granular deposit at bottom of depression. 



Plate Culture on Bouillon-agar. Colonies visible after 48 hrs. at 

 20° C. Surface colonies dirty white ; brown by transmitted light ; 

 round ; " wet-shining " ; raised | to 1 mm. above the surface ; domed. 

 Deep-lying colonies "punctiform." 



Streak Culture on Potato-mush-agar. After 24 hrs. at 20° C. streak 

 about 2 mm. wide and of a light chrome-yellow colour. 



. Streak Culture on cooked Potato. After 48 hrs. at 20° C. strong 

 growth and chrome-yellow colour, surrounding tissue of a mouse-grey 

 colour. 



Bouillon -f- 5. Bouillon turbid after 24 hrs. at 20° C. No pellicle 

 formed at the surface and no ring where the liquid meniscus came in 

 contact with the glass. After four days a considerable deposit had 

 formed at the bottom of the tube. 



Potato Broth. Became turbid after 24 hrs. at 20° C. On the second 

 day there was in one case a slight sign of a pellicle but this broke up 



