220 DEPART3IEXT OF THE NAVAL SERVICE 



8 GEORGE V, A. 1918 



Culturally and biocliemically this organism is a variation of the B. coli type 

 recording to the description of Escherich.^*^ The variety I have isolated differs from 

 the original description in that it is non-motile and ferments saccharose to acid and 

 gas. The degree of importance to be attached to any one character has been discussed 

 at considerable length in the literature during the last thirty years; owing to the fact 

 that this organism is used as a presumptive test for faecal contamination in systematic 

 water analysis. Of the two variations from the original type mentioned above, the 

 presence or absence of motility may first be considered. 



There has been a tendency by some workers to consider a non-motile form of B. 

 coli (Escherich)io as B. aerogenes (Escherich)^^. This position, hovvever, is not sub- 

 stantiated by the researches of Escherich and Pfaundler, MacConkey, Jackson and 

 others. Esclierich and Pfaundler^- in describing the original B. ooli state that generally 

 there is motility, sometimes slight; a characteristic movement as of short forward 

 pushes; swinging in space with sometimes no change of place is also noted. The 

 absence of definite motion as recorded by Tafel, Frankel and others is cited in the 

 same paper. Lembke'^^ considers that motility in B. coli is variable. McWeeney-^ 

 in discussing what he would regard as the genuine B. coli remarks : "on the motility 

 of individuals or its absence I hesitate to lay much stress." Houston^^ in using a 

 broad classification for the true colon group adopts his "flaginac" test which leaves 

 open the question of motility. Durham^^ considers that all members of the true colon 

 group are probably motile; but in the same paper states: "speaking generally morpho- 

 logical characters are not of much value for subdivision of these bacteria." 



MacConkey^''^ discusses the influence of temperature and medium on motility; and 

 while he considers the presence or absence as important he says : "it is very difficult to 

 arrive at a conclusion with regard to this character." Ellis^^ has proved the presence 

 of flagella in five species of the genus Bacterium which were hitherto held to be non- 

 motile; and he considers that all the genus Bacterium when suitably cultivated can 

 be shown to be motile. His conclusions would appear to be not sufficiently substantiated 

 on the data given. The English Commission on the Standardization of Methods for 

 the bacteriological examination of water^^; and the American Commission on Standard 

 llethods^ each specify motility as one characteristic of the true B. coli; but a com- 

 parison of the two standards reveals variance as to the significance to be attached to 

 this specific feature. Prescott and Winslow^" consider the sugar fermentations, par- 

 ticularly the fermentations of glucose and lactose, are of prime importance. Savage-^ 

 considers motility as one of the essential characters of the true B. coli/ Migula-- 

 includes B. neapolitanus (Emmerich)-^ which is non-motile, as identical with B. coli 

 (Escherich). 



Thus while the concensus of opinion is undoubtedly in favour of specifying 

 motility as a character of the true B. coli, there would seem to be no justification 

 according to present classification for excluding from this type an organism prepon- 

 deratingly similar and placing it with B. wrogenes (Escherich) ^^ on account solely of 

 the absence of motility. Harrison^^ raises the question as to whether, provided the 

 argument re motility is admitted, it removes B. neapolijtanus to a different genus from 

 B. rnli. 



The second variation to which I have referred (page 219) is the fermentation of 

 saccharose to acid and gas. B. coli (Escherich)^*' has no action upon saccharose. 

 Theobald Smith, cited by Prescott and Winslow^o stated in 1893 that B. coli could be 

 divided into two distinct sub-types, — the one negative to saccharose or in other words 

 the original B. coli, and the other fermenting this sugar to acid and gas. Durham^® 

 isolated saccharose — positive organisms and gave the name B. coli communior, since 

 contracted to B. communior. .Tackson^^ has classified the organisms of the lactose 

 fermentiic: type and confirms the sub-type B. communior of Durham. The classifica- 

 tion of Jackson has since been adopted by the laboratory section of the American 

 Public Health Association,^ and on this continent has received almost general approval. 

 Using saccharose and dulcito as differential fermentation tests Jackson considers 



