The functional structure of the normal rat liver was investigated in rapidly frozen, freeze‐dried tissue. The mean vascular volume of the liver was 27 per cent contrary to conventionally fixed tissue, in which this volume was 7 per cent. In the freeze‐dried tissue the sinusoids were systematic, orientated radially out to the periphery of the lobule. The bile capillaries were readily apparent contrasting to those of the delayed‐frozen or fixed tissue. A significant intracellular oedema of the liver cells was found to appear a few minutes after the cutting off of the blood s