Franklin P. Mall 291 
RELATION OF THE CONNECTIVE TISSUE TO THE STRUCTURAL UNIT. 
From the very earliest appearance of the liver, from the time the 
sprouts of epithelial cells invade the omphalo-mesenteric vein and break 
it into sinusoids, it is extremely difficult to demonstrate connective tissue 
cells within the liver substance. In all cases the endothelial cells lining 
the capillaries of the lobule come in apposition with the liver cells, and 
there are no nuclei between them. The cells which have been described 
as connective tissue cells have been abundantly proved to be von Kupffer’s 
stellate cells, and these are, according to von Kupffer’s last paper, the en- 
dothelial cells of the capillaries.” 
It is impossible to demonstrate sharp outlines to the lining cells of the 
capillaries of the liver lobule with nitrate of silver. Successful injec- 
tions show the markings in the portal vein until it reaches the lobule 
and there they stop. From now on the endothelial cells form an exten- 
sive syncytium with large openings through which the blood plasma comes 
in direct contact with the liver cells. However, there is a framework of 
fibers which has been described from time to time during the last fifty 
years as delicate, naked fibers which encircle the capillaries as they pass 
through the lobule.” This adventitia capillaris of His can be demon- 
strated by brushing fresh sections, but clear pictures were not obtained 
until special methods were invented for this purpose by Oppel” and by 
myself.” Oppel isolated the net-work by his special precipitation method 
which showed the thickness of the fibrils and their relation to the sur- 
rounding tissue. By my method all the cells were destroyed by digesting 
fresh sections in pancreatin, leaving only the fibrils which for special 
reasons were classed with the reticulum fibrils of the lymph node as well 
as those of other organs.” It is now generally admitted that the (it- 
terfasern and my reticulum are identical and that they form the frame- 
work of the lobule.“ That they are the same is shown by digesting a 
section upon the glass slide by the method of Spalteholz when pictures 
of reticulum identical in form and arrangement with the Gitterfasern 
are obtained. Upon the network of fibrils of reticulum which encircle the 
*% The extensive literature upon this subject may be found collected with a 
critical discussion in Oppel’s Lehrbuch, III, 1900. 
% Kupffer, Arch. f. Mik. Anat., LIV, 1899. 
33 Oppel, Anat. Anz., V, 1890; VI, 1891. 
3° Mall, Abhandl. d. K. S. Gescell. d. Wiss., XVII, 1891; and Johns Hopkins 
Hospital Reports, I. 
37 See also Mall, On the development of the connective tissues from the con- 
- nective-tissue syncytium. Amer. Jour. Anat., I, 1902. 
% Hoehl, Arch. f. Anat., 1897; and Oppel, Lehrbuch, III, p. 1009, 1900. 
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