One of the most important problems before the medical profession today is the relationship of the various protozoan intestinal parasites of man to disease. While there can no longer be any question of the vast importance of the pathogenic amoeba of man, Endamoeba histolytica, as a cause of disease in the human host, there is still much question as to the relationship of the various flagellates inhabiting the intestine of man to disease, and the diagnosis of all of the protozoan parasites of the human intestine is still unsatisfactory and demands much more study and investigation before it can be made available to the general profession in the way of reliable and practically useful technique. In this book Dr. Lynch has placed on record his extensive experience with these parasites, and his opinions regarding many of the questions which have been raised regarding their importance in human pathology.