BACTERIAL DESTRICTIOX OF COPEI'ODS 221 



SESSIONAL PAPER No. 38a 



those organisms positive to lactose and dulcite as B. coll (Escherich)^^^; positive to 

 lactose, saccharose and dulcite as B. communior (Durham)^^; positive to lactose and 

 saccharose but negative to dulcite as B. cerogenes (Escherich)ii, positive to lactose 

 but negative to saccharose and dulcite as B. acidi-lactici.--^ Further subdivision accord- 

 ing to the action on mannite and raffinose are used for further diiferentiation. 



MacConkey uses the Voges-Proskauer reaction as one of his diflerential tests and 

 finds that the true B. coli is always Voges-Proskauer negative, while the B. cerogenes 

 iyi:e is Vogei-Pr- skauer positive. In the same paper he revives chi ii.ime B. n-jooU- 

 tanus (Emmerich)-^ and uses this nomenclature for his saccharose positive dulcite 

 positive strains instead of the name given by Durham — B. cumin i-\'/.r. Ma.rMnkey 

 obtained a pure culture labelled B. neapolitanus from Krai, and out of 4S0 coli-like 

 organisms isolated from human and animal fjeces he found that 23 per cent gave bio- 

 ciiomical reactions identical with the Krai culture used by him as control. \lc states 

 that he cannot agree with Migula in describing B. neapolitanus (Emmerich) as iden- 

 tical with B. coli (Escherich). As, however, the differentiation by means of carbo- 

 hydrates other than glucose and lactose has been amplified since the classification by 

 Migula, the conclusions of both Migula and ]\racConkey on this particular point are 

 j.irfectly legitimate. Jordan-^, in designating the saccharose-positiva dulcite-p';sil,i.vo 

 group uses B. communior and B. neapolitanus interchangeably; biochemically 

 this as correct, but the former is motile (16), the latter non-motile^^. Levine-^ who 

 apparently follows MacConkey has lately studied 333 strains of lactose fermenting 

 bacteria from various sources. He goes one step further and giving B. neopolitanus 

 its original character of non-motility according to Emmerich-^, uses that nomen- 

 clature to include non-motile forms of B. communior (Durham). To say the least it 

 is interesting to revive B. neapolitanus as a sub-type of B. coli (Escherich) in view of 

 the following statement by Jordan^^**^ : " According to a strict application of the rules 

 of priority, the bacillus now known as B. coli should be called B. neapolitanus." The 

 dates of the original publication by Emmerich ~^^, and Escherich^^, of course bear out 

 Jordan's statement. 



However, according to the first descriptions of Emmerich-^ and Escherich^'^ the 

 former found a non-motile strain and the latter a motile strain of a lactose fermenting 

 organism. Later work already referred to has separated these two strains on the basis 

 of saccharose fermentation-*. We thus have two features in which the respective 

 strains differ. A propos of the stand taken by Durham and McConkey, Harrison-** 

 opens the question as to whether it is legitimate to name as a species, an organism 

 differing only in the fermenting of one sugar. 



It wovdd therefore seem legitimate, on the ground of present day classification, to 

 tentatively characterize the organism I have isolated-a non-motile, lactose, saccharose, 

 dulcite positive, Yoges-Proskauer negative strain, — as a variety of the sub-type 

 B. neapolitanus of the classic B. coli type of Escherich. To use B. neapolitanus con- 

 flicts with the nomenclature B. communior more usually accepted for the strains giving 

 identical reactions. If motility is considered, B. neapolitanus and B. communior are 

 not strictly the same; but to use the single characteristic, absence or presence of 

 motility, to separate B. communior and B. neapolitanus^ and at the same time to say 

 that a non-motile form of colon is identical with a motile form may seem inconsistent. 



The difficulty can be overcome by the tentative classification of the organism 

 I have isolated as a non-motile strain of the sub-type B. communior (Durham) of the 

 type B. coli (Escherich) ; or to take the differentation further, as B. neapolitanus, a 

 sub-type of B. coli (Escherich). 



Culture II. 



Morphology. — Microscopically — 24-hours-old agar culture at 37 °C.- — rods varying up 

 to 1-6 fi long and -8 ^ broad; some not much longer than broad; stains evenly 

 with Kiihne's methylene blue and is Gram negative. No spores; no capsules liave 

 been demonstrated. 



