ABSTRACT
Granule number and the amount secreted were correlated all right, but their relationship was variable, nonlinear. The portion of the cell occupied by granules decreased far more rapidly than their contents were secreted. As granules disappeared, much of what they had contained remained in the cell, presumably in the cytoplasm, awaiting subsequent secretion across the cell membrane. Even when most of the granules were gone, a significant fraction of their contents had yet to be secreted. The first was that the substances responsible for digestion were stored in the disappearing granules. The second was that the rate at which these substances were secreted was greater than the rate at which granules were replaced and the apparent decrease in their number. Finally, and most important to, Rudolf Heidenhain thought that this reduction was the result of granules popping out of cells, of their actually leaving the cell to enter the duct system.
