404 Profs. Percy Frankland and Marshall Ward. 



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 six, the latter usually exhibits ten to 

 twelve, whilst the cilia of the former are also far more fragile 

 (' Annales de 1'Institat Pasteur,' vol. 12, 1893, p. 561). It does not 

 form spores. 



Cultures : Gelatine Plates. Forms round, and very often oval, 

 smooth-rimmed granular 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 farrowed 

 appearance due to the unequal thickness of the colony in its different 

 parts. The colony also presents a distinctly wavy lineal structure 

 parallel to the periphery. No liquefaction ensues. 



Gelatine Tubes. Grows somwhat abundantly in the depth, pro- 

 ducing 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 surface, 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. Both cultures of twenty-four hours' age generally 

 exhibit considerable 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 un- 

 necessary for this purpose. Exhibits indol reaction 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 cause 

 peritonitis, and the bacilli are found in pure culture in the heart's 

 blood. (Alex. Fraenkel, ' Wiener klin. Wochenschr.,' 1891, N"os. 

 1315.) 



2. Behaviour of Typhoid Bacilli experimentally introduced into Potable 



Water. 



The second kind of information concerning the behaviour of the 

 typhoid bacillus in water has, as already mentioned, been gained by 



