BY R. GREIG SMITH. 621 



There are, however, many points of difference between the 

 chemical products of my bacilhis and those of Ritsert and Happ. 

 Since it is the products which mark the importance of the organ- 

 ism, and since these are different to the products of bacteria 

 ah'eady described, I have thought it advisable to give the organism 

 the distinctive name of Bacillus levaniformans. At the same 

 time it must be borne in mind that it is probably a variety of 

 Bac, vulgatus which^ together with several other allies, constitute 

 the potato group of bacteria. The members of this group of 

 bacteria have many points in common; in fact there are so man}^ 

 common characters that what are at present called species are 

 undoubtedly only races. To show this I shall enumerate shortly 

 the characters of these species as described by Lehmann and 

 Neumann, and it will be seen that Bac. levaniformans has affini- 

 ties wdth all the members of the group. 



The Mesentericus Group of Bacilli. 



Bacillus (mesentericus) vulgatus occurs as a thin rod, with 

 slightly rounded ends, measuring 0*8: 1-6-5 ju. It frequently 

 forms threads, and easily produces plump oval spores. The rods 

 are motile and are studded with flagella. The bacilli are stained 

 by Gram's method. On gelatine plates there are formed crateri- 

 form liquefied areas covered with a delicate whitish folded film. 

 In gelatine stab culture there is a crateriform liquefaction over a 

 filiform growth. On agar plate, there appear whitish, moist 

 glistening, raised, smooth or rough-edged colonies. When magni- 

 fied the centre of the colony appears homogeneous without mark- 

 ings, and the margin is often filamentous; the deep colonies are 

 homogeneous and frequently ciliate. The agar stroke is raised, 

 lobular, fatty and grey-white; after some time it becomes folded 

 and the condensed w^ater is covered with a strong film. Bouillon 

 is made turbid and forms a strong grey-white film; no indol is 

 formed. Milk is curdled and has a slim}'^ consistency ; the 

 reaction is strongly alkaline. The potato cultures are most 

 variable. The typical growth is raised and irregularly swollen 

 like the mesentery, whence its general name, Bac. mesentericus 



