482 Drs. Herring and Simpson. Relation of the [May 31, 



present an indistinct contour which is due to their having closely applied to 

 them a thin layer of connective-tissue fibres. The fibres are extremely fine 

 and occasionally stretch from vessel to vessel ; the capillary wall consists of 

 a layer of endothelial cells separated from the liver cells by the fine fibres 

 only. 



Wagner (61), in the same year, described in the liver a delicate membrane 

 everywhere surrounding the hepatic cylinders. It is different from the 

 capillary membrane, but is in close relationship with it, so that only one 

 delicate membrane separates the blood from the liver cells. The membrane 

 surrounding the liver cells he stated to be perfectly clear and homogeneous, 

 and of the greatest delicacy and transparency when normal. It has also a 

 further and peculiar property in possessing nuclei, and small cell-like 

 structures in its wall. The nuclei are constantly present, but differ in 

 number and arrangement; they are for the most part round and seldom 

 elongated. Other cells of an irregular or pointed shape occur, and belong to 

 the same membrane. A visible cement substance between capillary wall and 

 membrane of liver cells does not exist, but the two membranes are closely 

 applied to one another. 



Wagner pointed out that the liver differs from nearly all other organs in 

 the absence of connective tissue within its lobules. He laid emphasis on the 

 fact that the connective tissue of the liver never penetrates into the lobules 

 under normal conditions, and that any thickening of the membrane sur- 

 rounding the intralobular capillaries is of a pathological nature. 



In 1864, MacGillavry (42) described a space between capillary wall and 

 liver cell which he regarded as one of the sources of the lymphatics of the 

 liver. He found that the space is lined by connective-tissue fibres on the 

 side of the blood capillary and by liver cells and the walls of bile capillaries 

 on the other side. MacGillavry, therefore, differed from previous observers 

 in regarding the walls of the blood capillaries as having a less intimate 

 relationship to the liver cells, and being separated from them by perivascular 

 lymphatics. 



About the same time Carter (13) described in the capillary walls of the 

 liver nuclei which are filled with injection when carmine gelatine is injected 

 into the blood-vessels. He came to the conclusion that the nuclei instead of 

 being simply embedded in the walls of the capillaries are nucleated tubular 

 swellings which connect the blood-vessels with a " diaplasmatic system " of 

 vessels. Carter described plasmatic channels between the liver cells and 

 called them a " diaplasmatic system of vessels " or " intercapillary plexus." 

 He considered that blood plasma alone passes into them and that the 

 nucleated sheath of the blood-vessels allows the ready permeation of plasma, 



