INFECTIONS OF THE DIGESTIVE TRACT 9 



nistic action of the B. coli group has been more carefully 

 observed I shall speak of this only, especially as the 

 physiological behavior of its members is the more im- 

 portant on account of their wider distribution in the 

 digestive tract. 



The most far-reaching contention relating to the defen- 

 sive action of the B. coli group is based on the recent 

 observation of Conradi and Kurpjuweit l that the 

 members of this class make thermostabile and ther- 

 molabile substances which have a powerful antibacterial 

 action, being still active hi a dilution of 1 to 10,000 

 parts, and hence comparable to the antibacterial 

 action of carbolic acid. The inhibitory action of these 

 substances is stated to be not confined to alien bacteria, 

 but relates also to the B. coli group. The inhibition 

 in growth observed in old cultures was attributed to this 

 substance. Moreover, it was claimed that it is owing 

 to such bactericidal substances that the members of the 

 B. coli group tend to die out as they pass toward the 

 lower end of the bowel. It is easy to satisfy oneself 

 that the faeces of a healthy person contain more living 

 colon bacilli if the intestinal contents have somewhat 

 rapidly passed through the colon than if the usual so- 

 journ of material in the lower bowel has occurred. It 

 is also noteworthy that relatively few living representa- 

 tives of the B. coli class are present in the movements of 

 healthy persons with obstinate constipation. The cause 



ia Ueber die Bedeutung der bakteriellen Hemmungsstoffe fur 

 die Physiologic und Pathologic des Darms," Munch, med. Wochen- 

 schr., Hi, pp. 2164, 2228, 1905. 



