BACILLI RESEMBLING TYPHOID BACILLUS 411 



BACILLUS COLl-COMMUNIS 



Authority. Escherich, Fortschritte der Medicin, vol.iii., 1885, Nos. 16 and 

 17. Also Dunbar, ' Ueber den Typhus-bacillus und den Bacillus coli-communis,' 

 Zeitschrift f. Hygiene, vol. xii., 1892, p. 485. Also Luksch, ' Zur Differen- 

 zialdiagnose des Bacillus typhi abdominalis (Eberth) und des Bacterium Coli- 

 commune (Escherich),' Centralblatt f. Bakteriologie, vol. xii., 1892, p. 427. 



Where Found. In the intestinal tract of man and animals. Found in the 

 urine in cases of cystitis by Reymond, Annales des Organes Gdnito-Urinaires, 

 Paris, vol. xi., No. 10, p. 734. Found often in water by numerous investigators, 

 and frequently mistaken for the typhoid bacillus. 



Microscopic Appearance. The typical form is a short bacillus 0-4 /* broad 

 and 2 to 3 ju long ; it is, however, very variable, oval individuals and forms re- 

 sembling cocci being also found. It exists chiefly as a double bacillus arranged 

 in groups. It is slightly motile, and is provided with 1 to 3 cilia, whilst the 

 typhoid bacillus has 8 to 12 cilia (Luksch). Nicolle and Morax mention that 

 the Coli bacillus has invariably fewer cilia than the typhoid, that whereas the 

 former rarely possesses more than 6, the latter usually exhibits 10 to 12, whilst 

 the cilia of the former are also far more fragile (Annales de Vlnstitut 

 Pasteur, vol. xii., 1893, p. 561). It does not form spores. 



Cultures. 



GELATINE PLATES. Forms round and very often oval smooth-rimmed granu- 

 lar colonies in the depth, which later become yellowish brown in colour. On 

 the surface it forms flat irregular pale white expansions, which under a low 

 power exhibit a furrowed appearance due to the unequal thickness of the colony 

 in its different parts. The colony also presents a distinctly wavy lineal struc- 

 ture parallel to the periphery. No liquefaction ensues. 



GELATINE TUBES. Grows somewhat abundantly in the depth, producing small 

 white pin-head colonies, whilst on the surface it forms an expansion resembling 

 the growth on gelatine plates. 



AGAR-AGAR. Grows abundantly on the surf ace, producing a dirty white faintly 

 shining expansion. 



BLOOD SERUM. Forms a milk-white expansion. 



POTATOES. Produces a slimy yellow expansion on some potatoes, on others 

 grey white, whilst in some cases it resembles the typhoid bacillus in being 

 hardly visible. 



BROTH. Renders it turbid. 



MILK. Renders it acid, and at 37 C. coagulates it in from twenty-four to 

 forty-eight hours. 



Remarks. Broth cultures of twenty-four hours' age generally exhibit consider- 

 able evolution of gas ; ordinary gelatine or agar stab-cultures also generally exhibit 

 bubbles of gas in the solid medium. Such bubbles can invariably be obtained by 

 inoculating into ordinary melted gelatine, which is afterwards allowed to solidify 

 (Percy Frankland). The addition of dextrose to the gelatine is quite unnecessary for 

 this purpose. Exhibits indol reaction (see p. 273) after twenty-four to forty-eight 

 hours' culture in peptone broth. Is capable of exhibiting very different degrees of 

 pathogeneity according to its origin ; cultures made from diseased tissues in which it 

 is present on being intraperitoneally inoculated into rabbits causes peritonitis, and 

 the bacilli are found in pure culture in the heart's blood. (Alex. Fra,enkel, Wiener klin. 

 Wochenschr., 1891, Nov. 13-15.) Grows in formalin-broth (1 : 7000), see p. 285. 



