402 Profs. Percy Frankland and Marshall Ward. 



that it might possibly be due to the growth of the bacillus having 

 become enfeebled, I tried growing it under unfavourable conditions, 

 viz., in phenol-broth, in which I left the bacillua for months with- 

 out transplanting, but even by this severe treatment I found no 

 diminution in the indol-producing power. The absence of indol- 

 production by the B. coli communis has also been noticed by Dunbar, 

 who in his exhaustive memoir (Joe. cit.) compares the behaviour of a 

 culture of the typhoid bacillus with a culture of the B. coli communis, 

 and found that neither bacilli gave the indol-reaction. It is obvious, 

 therefore, that indol production is not a necessary attribute of the 

 B. coli communis, and that too much reliance must not be placed on 

 it as a means of distinguishing between the typhoid bacillus and the 

 B. coli communis. 



As convenient, for purposes of reference, I have collected in the 

 following two tables the principal characters of these two bacilli : 



Typhoid Bacillus. 

 (Bacillus typhi abdominalis.) 



Authority. Eberth, ' Virchow's Archiv,' vol. 81, 1880; also ibid., 

 vol., 83, 1881. Gaffky, " Zur Aetiologie des Abdominal typhus," 

 ' Mittheilungen a. d. Kaiserlichen Gesundheitsamte,' vol. 2, 1884, 

 p. 372. 



Where Found. In the blood, urine, faeces, as well as in the organs 

 of typhoid patients. Found by numerous investigators in water. 



Microscopic Appearance. A short, plump bacillus about three times 

 as long as broad, with rounded ends. It occurs in the tissues usually 

 singly, but in artificial cultures it grows frequently into long threads. 

 It is very motile and is provided with numerous cilia, which are 

 attached to both the sides and ends of the bacillus. To stain the 

 cilia add 22 drops of caustic soda to 16 c.c. of the mordant (Loeffler). 

 It is not stained by Gram's method, and stains less readily with 

 aqueous aniline solutions than most bacteria. Gunther recommends 

 heating the cover-glass, after the dye has been poured on it, for a 

 few seconds until it begins to steam, and then washing off the stain 

 as usual. It does not form spores. 



Cultures : Gelatine Plates. The colonies on the surface form large 

 spreading greyish-white iridescent expansions with jagged and ir- 

 regular edge. Under a low power they exhibit a brownish shimmer 

 and a characteristic woven structure. The depth colonies are darker, 

 with regular edge, and are covered with delicate irregular lines. No 

 liquefaction takes place. 



Gelatine Tubes. Grows chiefly on the surface, producing a delicate 

 greyish-white iridescent expansion with irregular edge. 



Agar-agar. Forms a greyish-white moist expansion. 



