The location of silver in frog epidermis after treatment by ranvier's method,and possible implication of the flask cells in transport

Summary Frog skin, bladder wall, and sciatic nerve were treated by Ranvier's silver nitrate method and subsequently fixed and sectioned for electron microscopy. In the epidermis of the skin, more silver is found deposited in the flask cells than elsewhere, especially as a sub-apical plaque in the neck of the flask, which appears after the skin has been flooded with silver nitrate for 5 minutes. Mitochondria rich cells in the bladder also accumulate more silver than the surrounding epithelial cells, but do not show such a distinct sub-apical plaque. In myelinated nerve fibres treated similarly, silver accumulates in the paranodal regions of the axon, and outside the axon at the node. It is suggested that silver may accumulate near a site of ion transport, due to structural specialisations not visible by standard electron microscope techniques, and that the flask cells may therefore be implicated in transport in the frog skin.