Summary 1. The routine measures employed in the examination of the patients admitted suffering from dysenteric symptoms is described. 2. The difficulties in the diagnosis of dysenteric conditions are discussed especially the difficulties experienced owing to the late arrival for treatment of cases of bacillary dysentery. 3. Negative stool examination results in amœbic cases, even when the disease is acute is noted, and the cause of this negative finding is considered. 4. The absence of ova in the stools of some bilharzial cases is described, negative results in some cases persisting even when material obtained by a Volkmann spoon scraping through the sigmoidoscope is examined microscopically. 5. The routine method employed in carrying out sigmoidoscopic examination is described, the importance of preliminary preparation of the bowel being emphasised. 6. The typical sigmoidoscopic appearances in bacillary, amœbic, and bilharzial dysenteries are depicted, and the great assistance rendered by the use of this instrument in the elucidation of such diseases is pointed out. 7. The importance of bilharzial involvement of the bowel as a cause of dysenteric symptoms in Egypt is shown; the resistance of these cases with papilloma formation to all the usual forms of treatment being noted. 8. A table giving the results of our investigations in 150 cases of dysenteric conditions controlled by repeated sigmoidoscopic examination is shown, the benefit to be derived from the use of this instrument in the diagnosis of these conditions being apparent.