This probably explains the endemic rather than the epidemic characteristics of the spread of amoebic dysentery because, if the innumerable vegetative amoebae in dysenteric stools were equally operative with the more sparsely eliminated cysts, there would be epidemics of amoebic dysentery similar to those of bacillary dysentery. The old idea that water, fruit or vegetables, from which one can isolate amoebae on culture, are sources of infection must be abandoned, as such cultural amoebae are known to have no pathogenic relation to man. Vegetative amoebae undergo disintegration in a short time after the stool is passed, so that they are probably rarely concerned in amoebic infections but the resisting cysts may be washed from a dried stool into a water supply or even be transported in dust to lodge on unprotected foodstuffs. Flies may possibly act as transmitting agents. As bearing on the probable importance of such flies as _Musca domestica_ and _Fannia canalicularis_ in transmitting amoebic infections may be noted the findings of Wenyon that the faeces of such flies, as well as _Lucilia_ and _Calliphora_, after feeding on cyst-containing human faeces, teem with such cysts. In a dissection of 1027 house flies caught in Mesopotamia Buxton found ova of parasites of man in 4.09%. The percentage of infection with _E. histolytica_ cysts was O.3%. PATHOLOGY Wenyon thinks that the pathogenic amoebae work their way into the tubular glands of the intestines and multiply and subsequently, either by pressure of their pseudopodia or through the disintegrating action of some toxic substance elaborated by them, they force their way into the underlying submucosa. In this location they produce a gelatinous, oedematous necrosis, which shows a marked absence of polymorphonuclears, but a proliferation of connective tissue cells. The process is regenerative rather than inflammatory.