One cannot have experienced the war without having been impressed anew, and depressed, by the amount of parasitism in the world. Speak-ing helminthologically, it may be referred to as the grave host r6le which the lives of men play in the lives of worms. Or, think of it the other way about, for there is likewise the great parasitic role the lives of worms play in the lives of men. Back from the Pacific come a thousand-odd Americans with schistosomiasis, and a few times that many with filariasis, and several multiples more with ancylostomiasis (sensu strictu). To homes widely dispersed throughout the land go these exservice men, to live a lifetime in familiarity with the strangely sounding names of their distantly-acquired helminthiases. These observations suggest familiar concepts to the parasitologist.

The One World of Wendell Wilkie that struck with the force of a new idea at the politicoeconomic level, is, of course, decades, and in some respects centuries old, to the student of disease-producing agents. However, each parasitologist is wont to live in his thinking in One World with the species which particularly interests him. There have been, therefore, only a few attempts to bring all species of major human concern into the short focus of a brief presentation. In the belief that there might flow from such renewed consideration certain emphasis useful to world citizens and in our science, this attempt at such a suc-cinct statement has been made.