Before discussing the pathology of amebiasis in carriers, it is necessary to define the term “amebiasis.” By “amebiasis” I understand the state of infection of man with Endamœba histolytica whether symptoms of the infection are present or absent. The term includes the amebic carrier state, those cases presenting mild or atypical symptoms of infection, those presenting diarrhea as a prominent symptom, and lastly, those developing the characteristic clinical picture known as amebic dysentery and the complications known as amebic abscess of the liver and other organs. It will be noted that in this definition amebic dysentery is considered merely as one stage in amebiasis. The conception that the terms “amebiasis” and “amebic dysentery” are synonymous is now obsolete and should be abandoned. INCIDENCE OF INFECTION The numerous surveys that have been made in the United States and other countries for the purpose of determining the incidence of infection with Endamœba histolytica have demonstrated that it has a world-wide distribution.