206 INFECTIONS OF THE DIGESTIVE TRACT 



nervous system. Persons suffering from severe forms of 

 chronic infection by this organism almost always show 

 signs of intoxication of the nervous system, but such 

 manifestations are very different in different individuals. 

 It is not yet clear whether the gas-bacillus makes 

 a substance capable of exciting an acute inflamma- 

 tion of the ileum or colon or whether preceding 

 mechanical or chemical irritation is necessary to enable 

 the organism to multiply rapidly and excite further 

 inflammation. Healthy monkeys may be fed consider- 

 able numbers of capsulati without developing signs of 

 inflammation in the intestine, although such feeding is 

 followed by an increase in these organisms in the faeces. 

 Two monkeys fed on gas livers from incubated rabbits 

 infused with pure cultures of B. aerogenes capsulatus 

 developed soft stools temporarily. Such experiments 

 are, however, quite different from the experiment of 

 introducing capsulati into a digestive tract already 

 somewhat inflamed and irritable in consequence of pre- 

 ceding infections. The ability of B. aerogenes cap- 

 sulatus to cause an inflammatory necrotic process in the 

 muscles of guinea-pigs and pigeons, which was noted 

 by Dr. Flexner many years ago, is of interest in this 

 relation. It appears probable that B. aerogenes cap- 

 sulatus is often the cause of slight inflammatory or per- 

 haps even necrotic changes in the mucous membrane 

 of the intestine. Howard * has described instances of 



1 "Contributions to the Science of Medicine, Dedicated by his 

 Pupils to William Henry Welch on the 25th Anniversary of his 

 Doctorate," Baltimore, p. 461, 1900. 



