PATHOGENIC BACTERIA. 381 



W hile the idea formerly entertained that sewer gas is itself 

 the cause of typhoid fever, Horrocks* points out that the 

 bubbles of gas in sewage may be the means of spreading the 

 contagium. 



The injection of typhoid bacilli which have been killed by heat has been 

 resorted to as a preventive measure in a large number of cases in the British 

 army. The results appear to have been partially successful, but the method 

 is still in an experimental stage. 



Richardsonf sums up his results with the use of specific sera, filtrates from 

 cultures, and non-toxic extracts from cultures (Vaughan) approximately as 

 follows: Seventy-four cases were treated i)y various methods with serum 

 prepared by inoculating horses with typhoid cultures as in the method of pro- 

 ducing diphtheria antitoxin; 35 cases were treated vidth the filtrates through 

 porcelain filters of cultures of typhoid bacilli; 21 cases were treated with non- 

 toxic extracts of the typhoid bacillus prepared by Vaughan. All these methods 

 increase the tendency to relapse unless the Vaughan non-toxic treatment is 

 kept up into the stage of convalescence. The use of serum has no advantages 

 over the filtrates and extracts upon the course of the disease. Filtrates may 

 produce chills, rise of temperature and pulse, followed by a general improve- 

 ment in the clinical aspect. The non-toxic residue of Vaughan seems to make the 

 typhoid process longer, but milder, and to prevent relapse in convalescence. 



Bacillus coll communis (often called simply the colon 

 bacillus, Bacterium coli commune of Escherich, and Bacillus 

 pyogenes foetidus of Passet, who obtained it from foul pus; 

 probably the same as Bacillus Neapolitanus of Emmerich).— 

 A bacillus with rounded ends, frequently of a short, oval form, 

 when it may be difficult to distinguish from micrococci; often 

 longer, even forming threads. It is slightly motile, having 

 several fiagella. It does not form spores. It stains with 

 the ordinary aniline dyes, but not by Gram's method. It is a 

 facultative anaerobe. It grows well at the room-temperature, 

 but more rapidly in the incubator. It does not liquefy gelatin. 

 In gelatin plates the surface colonies are of a bluish-white color; 

 the centers are denser than the borders, which are translucent. 

 It usually grows more rapidly in gelatin than the bacillus of 

 typhoid fever. Its growths in other media are mostly whitish. 

 Bouillon becomes clouded. Nitrates are reduced to nitrites. 



*Ed. in Journ. Am. Med. Assn. Vol. XL VIII., June i, 1907. p. 1869. 

 fAnnual Meeting of the Massachusetts Medical Society, Boston. June 11, 



too?- 



