INFECTIONS OF THE DIGESTIVE TRACT 125 



capsulatus is really identical with the granulo-badllus 

 immobilis liquefaciens of Grassberger and Schattenfroh 

 (as is claimed by some observers and denied by others, 

 including Fraenkel), this method may prove helpful in 

 connection with the study of some diarrhoeal diseases 

 which have been attributed to the use of infected milk. 



There is reason to think that the faecal suspensions 

 from most persons in good health would induce gas pro- 

 duction in incubated rabbits, since the faeces of most 

 apparently normal persons contain moderate numbers 

 of B. aerogenes capsulatus. The difference, as regards 

 the outcome of the incubation experiment, between the 

 flora of these persons and the flora of persons with cap- 

 sulatus infections is probably one of degree and not of 

 kind. Some idea of the relative numbers of capsulati 

 present might perhaps be gained by determining the small- 

 est volume of a given fsecal suspension that will just suf- 

 fice to induce the distinctive gas production in incubated 

 rabbits within a given time. 



As it was obviously impracticable to isolate in every 

 instance the dominant microorganisms of the faeces, it 

 was resolved to study the action of the mixed faecal flora. 

 This was done in the hope of obtaining information which 

 should be of service in determining what bacteria are 

 really dominant in the intestine. The effort has not 

 been wholly successful, but has, nevertheless, proved 

 useful in several ways. A suspension of the mixed flora 

 was prepared in normal salt solution in the proportion 

 of about one part of material by weight to ten parts 

 of the solution. From this suspension a series of 



