356 THE COLI CLOACAE PROTEUS GROUP 



both a maltase and a lactase in maltose and lactose cultures of the 

 organism respectively. The investigations of Franzen and Stuppuhn 1 

 would suggest that the liberation of gas in sugar broth cultures of 

 B. coli and other aerogenic bacteria depends upon the production 

 of formic acid from the carbohydrate and its subsequent decomposi- 

 tion into carbon dioxide and hydrogen by the action of an enzyme, 

 formiase, in accordance with the equation H.COOH = CO 2 + H 2 . 



(c) Toxins. Bacillus coli does not produce a soluble toxin. The 

 injection of killej cultures into laboratory animals frequently causes 

 death; if large amounts are introduced intravenously into rabbits 

 there is usuaUy a lowering of the body temperature, diarrhea, collapse 

 and death even within three hours. 2 If the animals survive for a 

 longer time a purulent peritonitis may develop. Living cultures of 

 colon bacilli derived from inflammatory processes in man are gen- 

 erally virulent for guinea-pigs. Old stock cultures ark less virulent 

 as a rule. The symptoms of toxemia which are exhibited by labor- 

 atory animals following the injection of colon bacilli are probably 

 caused by the liberation of endotoxins from the bacilli. 



Pathogenesis. The colon bacillus is a normal inhabitant of the 

 intestinal tracts of man and the higher animals. Ordinarily it is a 

 harmless parasite, but it may become invasive if conditions arise 

 which weaken the intestinal mucosa. In peritonitis, purulent per- 

 forative appendicitis, angiocholitis, and even in occasional cases of 

 pancreatitis the organism is frequently isolated, either in pure culture 

 or in association with other bacteria, as streptococci, typhoid bacilli, 

 or staphylococci. It is difficult to determine with precision the part 

 played' by Bacillus coli in these conditions. Occasional cases of enter- 

 itis are encountered which appear to be caused by this organism, 

 other bacteria having been ruled out. The careful studies of Coleman 

 and Hastings 3 are of great importance in this connection. They 

 isolated colon bacilli from the blood stream in a small series of cases 

 which presented symptoms indistinguishable from those of typhoid 

 fever. No typhoid bacilli were ever found in these patients, and no 

 specific agglutinins for the typhoid bacillus were demonstrable. 

 Specific agglutinins for the homologous strains of B. coli persisted 

 until recovery. Cystitis and pyelonephritis, particularly the former, 

 are frequently found to be a pure colon infection. B. coli is occa- 



1 Ztschr. f. physiol. Chem., 1912, Ixxvii, 129. 



2 Escherich, Fort. d. Med., 1885, 521. 



3 Med. and Surg. Report of Bellevue and Allied Hospitals of the City of New York, 

 1909-1910, iv, 56. 



