“…These may include the study of small intestinal transit time [Bond and Levitt, 1975;, the metabolism of dietary fibre in the colon [Hickey, Calloway and Murphy, 1972;Tadesse and Eastwood, 1978), the diagnosis of disaccharidase deficiencies [Calloway and Murphy, 1968;Metz, Gassull, Leeds, Blendis and Jenkins, 1976;Newcomer, Thomas, McGill and Hofmann, 1977], small intestinal bacterial colonisation [Metz, Gassull, Drasar, Jenkins and Blendis, 1976] and pneumatosis cystoides intestinalis [Gillon, Tadesse, Logan, Holt and Sircus, 1978; Van der Linden and Marsell, 1979], and the study of bacterial activity in the gut [Gilat, Ben Hur, Gelman-Malachi, Terdiman and Peled, 1978]. The central principle in most tests is that any carbohydrate which is not digested and absorbed in the upper small intestinal tract (i.e.…”