24 HILDA HEMPL HELLER 



meat particles do not dimmish in size. Sugars are attacked. 

 Milk is digested. Gram-positive rods which readily form oval 

 subterminal or median spores. Colonies minute, opaque, com- 

 plex, yellow. Typically toxic tissue invaders which produce in 

 the guinea-pig a clear white oedema that does not rapidly lose 

 its ©edematous nature on section. 



Type species R. progrediens nov. sp. To be described in a 

 future paper. Two species, one found in a case of human gas 

 gangrene (see Barney and Heller), the other in a sheep. 



Genus 18. Rohertsonillus nov. gen. 



Putrificoideae that produce on meat medium a little gas and 

 a terra cotta coloration, multiplying slowly for a long period. 

 A black pigment is absent. Sugars not fermented. Weakly 

 Gram-positive or Gram-negative rods with oval spores, usually 

 subterminal, that somewhat distend the bacillus. Two spores 

 often occur in one rod. In old cultures enormous snakey Gram- 

 negative rods are produced. One species, found twice in wounds. 

 Non-pathogenic for guinea-pigs in pure culture. 



Type species R. primus (Bacillus I, Hempl) as described by 

 Hempl. Descriptions of bacilU similar to this have not been 

 noted. Proteolytic organisms producing a terra cotta colora- 

 tion in meat medium are not uncommon, however. 



Genus 19. Nicolaierillus nov. gen. 



Putrificoideae that in meat medium produce gas and various 

 color changes: yellowish, pink, grey or mauve, depending on the 

 medium; the particles of meat are gradually suffused with a 

 black pigment, and bleach at the top. The meat is softened 

 but the particles do not greatly dmiinish in size. Do not attack 

 sugars. Gram-negative (weak methyl violet) rods that form 

 terminal spherical spores. Colonies in deep agar diverse. Com- 

 mon in soil, found in horse feces, maj'^ multiply in wounds, but do 

 not normall}'^ invade tissue. Produce a characteristic neuro-toxin. 



Type species N. tetani (Bacillus tetani Nicolaier), to be de- 

 scribed in a future paper. 



Tulloch flOl? and 1919) has divided the group into four types 

 on the basis of the agglutination reaction. Adamson (1920) 



