Despite the fact that Strongyloides infections are very prevalent in the tropics, and also, although to a lesser extent, in some countries with more temperate climates, a glance at any of the well-known textbooks on tropical medicine and parasitology will suffice to show that on the subject of the pathogenic power of this parasite, much uncertainty and conflictions of opinion exist. Since the time that Normand (1, 2) first encountered the larvae of Strongyloides in diarrheic stools and later found the minute parent generation in the mucosa of the small intestine of some of the fatal cases of diarrhea not uncommon at the time among the repatriated troops from Cochin China, and came to attribute the disease to infestation with this parasite, a great deal of opposition against the view that this organism was the specific cause of the so-called Cochin China diarrhea has arisen.