A cytological study on the liver of the rat, with special reference to the ‘intracellular blood canaliculi,’ inter‐ and intracellular bile canaliculi, mitochondria and Golgi apparatus

In sections from livers injected through the vascular system with Carter's carminegelatin or Berlin‐blue gelatin masses at known, constant pressures, many cells were observed to contain ovoid or spherical bodies of the colored injection masses, similar to those described by Schäfer and his students, Herring and Simpson, as intracellular blood canaliculi.' In these livers practically all the cells were vacuolated. However, with livers injected with Berlin‐blue gelatin mass dissolved in Locke's solution instead of distilled water, there were no intracellular masses and the cells appeared normal, though the sinusoids were completely filled with injection mass. The so‐called ‘intracellular blood canaliculi’ described by Schäfer are interpreted as artefacts produced by a combination of factors, the most important of which is the difference in osmotic pressure. This is produced by the hypotonicity of the injection masses that are usually used, augmented perhaps by the effect of mechanical pressure used in administering the injection mass. Following impregnation of liver tissue by Golgi's rapid method, the usual network of intercellular bile canaliculi was revealed, but the presence of a permanent system of intracellular canaliculi was not observed. A few short, knobbed intracellular projections from the intercellular bile canaliculi were noticed; these probably represent the passage of secretion material into the intercellular bile canaliculi at the moment of excretion.