1906.] Liver Cells to the Blood-vessels and Lymphatics. 459 



They stated that the injection material penetrates between the liver cells 

 and finds its way into them by one or more fine channels, reaching even into 

 the nucleus and ending in knob-shaped dilations. Increase of injection 

 pressure causes an accumulation of the injection mass in reservoirs or 

 vacuoles in the cell protoplasm, but does not distend to any appreciable 

 extent the fine passages leading to them from the blood-vessels. The 

 brothers Fraser concluded that in the frog at least a system of fine plasmatic 

 channels exists in the liver, too small to admit the corpuscles of the blood, 

 but affording a direct means of communication between the blood plasma and 

 the interior of the liver cells. 



Nauwerck (46), after reading Fraser's paper, looked carefully over a series 

 of preparations of injected human livers, and found the injection present in 

 the liver cells, often in ring-shaped canals round the nucleus, but never 

 penetrating into it. Nauwerck described two intra-cellular networks of fine 

 channels, one system belonging to the bile ducts and revealed by special 

 stains, the other pertaining to the blood-vessels. 



Browicz (9), from a study of normal and pathological human livers, and 

 from the result of the intravenous injection of solutions of haemoglobin in the 

 dog, came to the conclusion that there must exist in the liver cells special 

 afferent nutritive channels or canaliculi. These channels convey plasma and 

 even red blood corpuscles directly to the nuclei of the liver cells. The red 

 blood corpuscles are broken down in the cells, and the haemoglobin is stored 

 in the nuclei and converted into bile pigment ; a second set of fine intra- 

 cellular channels conveys the bile as it is formed into the bile canaliculi. 

 Browicz (8) doubted the presence of perivascular lymphatics round the liver 

 capillaries, and believed in a communication between the blood capillaries 

 and the cytoplasm and even the nuclei of the liver cells. He found red 

 blood corpuscles in various stages of disintegration in the liver cells. If in 

 the dog's liver haemoglobin had been injected intravenously some hours before 

 death, free haemoglobin and crystals of haemoglobin were present both in the 

 cytoplasm and in the nuclei. Browicz did not see the intracellular canaliculi, 

 but argued that they must be present, though exceedingly fine. 



In 1901 Schafer(55) described specimens of livers of rabbit and cat in 

 which the liver cells everywhere contained networks of injection material — 

 carmine gelatine — which had entered them from the blood-vessels. The 

 livers had been injected from the portal vein, but no record of the pressure 

 employed had been kept. Schafer described the injection within the cells as 

 " confined within sharply-defined, somewhat varicose, intercommunicating 

 canaliculi, many of which are in the immediate neighbourhood of the nucleus 

 or nuclei," but he did not observe any injection actually within the nuclei. 



