_Iodine Cysts._—These bodies which stain a deep brown colour when treated with iodine are now recognized as amoebae and have been named _Iodamoeba bütschlii_. They are most probably nonpathogenic. It is a small amoeba (9 to 13 microns, rarely up to 20 microns) and shows the sluggish movements of _E. coli_. The nucleus is very difficult to discern, thus differing from _E. coli_. In stained specimens it has a vesicular nucleus about 2 microns in diameter with a fairly large central karyosome. The cysts are spherical or oval, often of irregular outline and are about 10 microns in diameter. The nucleus is large and eccentrically placed and has a karyosome which tends to show as a peripherally placed mass. There is almost always present a large glycogen mass in the cyst which stains intensely with iodine. _Dientamoeba Fragilis_ (Jepps and Dobell 1918).—A rare binucleate amoeba averaging 8-9 microns in size. Nuclei show a fairly large, central granular karyosome and no peripheral chromatin. Strands of linin may be seen radiating from karyosome to nuclear wall. This organism is said to be frequently mistaken for Blastocystis when the vacuoles coalesce leaving a thin ring of cytoplasm. Cysts unknown. Considered nonpathogenic. Recently Kofoid and Swezy reported another species of amoeba parasitic in man, _Councilmania lafleuri_. The adult and cystic stages resemble in many respects the _E. coli_. Adult said to ingest red blood cells. Stated to be pathogenic but that more evidence is needed on this point. =Human Experiments.=—Recently Walker and Sellards have published a most important paper. The experiments were made in men who had been under observation for years at Bilibid Prison, whose food was cooked and the water they drank distilled. Moreover, there were complete records of examination for intestinal parasites, including entamoebae. They were under complete control and the existence or possibility of natural infection with amoebae was reduced to a minimum. All the men fed pathogenic amoebae were volunteers and each signed, in his native dialect, an agreement to the conditions of the experiment. The first series of experiments was with cultural amoebae, in order to refute statements that amoebae cultivated from water or other nonparasitic sources, as well as from dysenteric stools, are capable of living in man parasitically or of producing dysenteric symptoms. Twenty feeding experiments on ten men were made by Walker and Sellards with cultures of amoebae without the development in a single instance of dysentery or the finding of such amoebae in the stools upon microscopical examination. In 13 cases they recovered the amoebae in cultures from the faeces from the first to the sixth day, but never afterwards. They stated definitely that cultural amoebae are nonpathogenic.