18 INFECTIONS OF THE DIGESTIVE TRACT 



inhibition described by Conradi and Kurpjuweit and by 

 Moro and Murath is not yet entirely clear. That the 

 observed inhibition is due to complex cellular products 

 the " autotoxines " of Conradi is questionable in view 

 of the studies of Manteufel, 1 of Passini, 2 and of Oebius. 3 

 Manteufel showed that in many cases where the surface 

 of a plate indicated no growth on inspection, and where 

 consequently it would be assumed that an inhibitory 

 effect had been exerted, in reality many small micro- 

 scopical colonies were present. In other words, the 

 character of the growth may be of such a nature as to 

 mislead one into the belief that inhibition has occurred 

 where in reality such inhibition is absent or slighter than 

 has been supposed. In these cases the size of the in- 

 dividual surface colonies was smaller but their number 

 was increased and the surface could certainly not be 

 regarded as sterile. Further observations made it very 

 probable that the exhaustion of the culture medium 

 incidental to the growth of the faecal flora is in part the 

 cause of the failure of the surface colonies to grow. 

 The assumption that there are produced in the bouillon 

 culture thermolabile, unfilterable, and dialyzable sub- 

 stances which check the growth, appears unwarranted in 

 the light of certain experiments with reference to this 



1 "Untersuchungen iiber die 'Autotoxine' (Conradi) und ihre 

 Bedeutung als Ursache der Wachstumshemmung in Bakterien- 

 kulturen," Berl. klin. Wochenschr., xliii, p. 313, 1906. 



2 "Die bakteriellen Hemmungsstoffe Conradis und ihr Einfluss 

 auf das Wachstum der Anaerobier des Darms," Wien. klin. 

 Wochenschr., xix, p. 627, 1906. 



3 " Ueber spontane Wachstumshemmung der Bakterien auf 

 kiinstlichen Nahrboden," Med. Klinik, ii, p. 598, 1906. 



