274 Profs. Percy Frankland and Marshall Ward. 



Taking the large size of the bacillar segments as oar primary clue, 

 the vast majority of known bacillar or filamentous schizomycetes 

 rarely exceed 0'5 /t in diameter, and very few surpass 1 fi. 



Of these, we may at once dismiss Van Tieghem's giant B. crassus, 

 4 fi in diameter, and the thickest form known,* and even De Bary's 

 B. megaterium, 2*5 /* in diameter, is much thicker than the form I am 

 discussing. 



A small number of species, such as B. Brassica, B. tumescens, 

 B. Zopfii, B. Mallei, B. ascoformans, B. indigogenus, approach our form 

 in dimensions, but their other characters at once separate them. 



B. anthracis presents several suggestive resemblances to the present 

 schizomycete, but it is thinner and smaller altogether, and its spores, 

 in addition to being smaller, genninate differently, and have differ- 

 ent temperature requirements. Moreover, though the stab-cultures 

 of B. anthracis resemble those of the Thames form, the gelatine plate 

 cultures are different. The spores of the former are also much more 

 sensitive to light, and the Thames species is not pathogenic. 

 Maschek's " Bciumchen-bacillus," though it forms a dendroid stab- 

 culture, differs in almost all its other characters, and ferments 

 saccharine solutions. 



As regards the tendency to form mycelium-like colonies on the 

 plates, several species found in water and elsewhere resemble the 

 Thames species, e.g., B. radiatus, B. muscoides, B. polypiformis, B. 

 mycoides, B. ramosus, B. implexus.^ 



Of these, we may rapidly dismiss B. muscoides, B. poly pif or mis, and 

 B. radiatus, since they are strictly anaerobic, and will not grow under 

 ordinary conditions, to say nothing of their many other specific 

 differences. 



B. implexus is too thin, and Zimmermann's curt description of 

 the colonies suffices to show that it is totally unlike the Thames form. 

 B. mycoides is also too thin, but it forms oval spores, and the plate- 

 cultures resemble those of the form in question in many particulars. 

 The potato-cultures differ, however. More information is wanted 

 about this species, which is said to be very common in soil and water. 



There remains B. ramosus. I understand by this specific name the 

 form described by EisenbergJ under that name, and known in 

 Germany as the " Wurzel-bacillus." Crookshank gives the latter 

 under the name B.figurans, and as a synonym for Flugge's.B. mycoides, 

 but Eisenberg gives quite a different description for the latter, and 

 quotes Fliigge and Zimmermann in support of his statements. 



* Q.uoted by De Bary, ' Lectures on Bacteria,' p. 3. Of course I leave out of 

 account the genera Crenothrix, Beggiatoa, &c. 



t See Lustig, ' Diagnostik der Bakterien des Wassers,' 1893, p. 82. 



Loo. tit., p. 126. 



' Manual of Bacteriology,' 1887, p. 311. 



