In the article by Nguyen et al in this issue (see page 624), a novel impedance method was used to characterise the transport of chyme in the duodenum in the postprandial period. The authors suggest that abnormal postprandial transport of chyme in the duodenum may be a factor that results in impairment of gastric emptying in patients with long-standing type I diabetes mellitus. The paper raises a number of interesting issues.

The first question is: does the human duodenum actually perform any hydrostatic or pumping function? In a previous in vitro model, Weems1 suggested that the cat duodenum was incapable of hydrostatic function, in contrast to the ileum. This observation was supported by the very different nature of contractions observed in the mammalian upper …