A blood shunt explaining intermittency of function of the stomach, to our knowledge, was first suggested by Barlow, Bentley, and Walder in 1951.1 These men demonstrated the shunt functionally by perfusion experiments and by radiophotomicroscopy. These findings are in accord with Zweifach's basic concept of the functional capillary unit,2 which is arranged so as to bypass tissue at rest, except for maintenance blood supply, and so as to flood the capillaries when work is demanded of the tissue in question. Zweifach reported his concept in 1939. It is illustrated in Figure 1.
In 1954,3 we reported a comparison of the number of blood-filled capillaries per square millimeter between ulcerative and nonulcerative disease of the stomach. These counts were made by calibrating a standard monocular microscope field against a blood-counting chamber. There was demonstrated from the slides of the University of Michigan in Ann Arbor, Department of Pathology,