312 MANUAL OF BACTERIOLOGY. 



red in media, and the colon bacillus to change it to a yellow 

 color. 



To these may be added the growth of the two organisms 

 on special media like those of Wurtz, of Eisner and of 

 Hiss, and the application of the serum-reaction. 



Injections of cultures of the bacillus coli communis into 

 animals produce variable and uncertain results. Subcuta- 

 neous injection may lead to pus-formation ; in rabbits and 

 guinea-pigs injections may produce death apparently from 

 poisons introduced. With the blood of immunized animals 

 a serum-reaction, similar to that described for typhoid fever, 

 may be demonstrated. 



Concerning the occurrence of the bacillus coli communis 

 in the intestine of man, see page 155.* 



At autopsies on human subjects the great viscera are 

 often found to have been infected by the colon bacillus, 

 usually when some lesion of the intestine existed simul- 

 taneously, but in most cases without having produced much 

 apparent damage to the organs invaded. The bacillus coli 

 communis frequently occurs in mixed infections, as in 

 wounds, inflammations and abscesses. It is often found in 

 the peritoneum in peritonitis, in the pus in appendicitis, 

 and in the urine in cystitis; it frequently occurs in the in- 

 terior of gall-stones with whose formation it may be con- 

 nected. 2 



There is a large number of more or less closely-related 

 organisms which go by the name of the "colon group." 

 The limits of the colon group are extremely ill-defined. 



Paracolon or paratyphoid bacilli are the names applied to certain 

 members of the colon group which have recently been shown to be 

 pathogenic to man. They may produce clinical symptoms resembling 

 typhoid fever of a mild and atypical form. The affection is rarely 



1 See also Moore and \Yright, " Bacillus coli communis in the Do- 

 niesticnu-d Animals." American Medicine, March .'<). K;O-'. 



2 Lartigau, Journal American Medical Association, April 12, 1902. 



