STRUCTURE OF THE LIVER. 1715 



outline and measure usually from .015-025 mm. in their longest dimension. Each 

 cell comes into contact with from six to nine other elements, the surfaces of contact 

 being plane from mutual pressure. Always one side, often more than one, exhibits 

 a shallow depression which indicates the surf^ice of former contact with a capillary 

 and emphasizes the intimate relation existing between the blood-vessels and the cells. 

 The latter lie against at least one capillary and sometimes several, this relation being 

 dependent upon the size of the blood-channels. The larger the latter, as at the 

 periphery and near the centre of the lobule, the greater the number of cells with 

 only one or two capillary facets ; conversely, where the capillaries are of small 

 diameter, the cells come into contact with three or four. The liver-cell consists of 

 finely granular protoplasm which sometimes exhibits a differentiation into an outer 

 and an inner zone. It is without a cell-membrane, although the peripheral zone 

 of its cytoplasm is condensed, especially when it forms part of the wall of the bile- 

 canaliculi. The nucleus, of vesicular form and from .006-.008 mm. in diameter, 

 contains a small amount of chromatin and usually a nucleolus. Occasional cells 

 are conspicuous on account of their large size, as well as the unusual diameter of 



Fig. 1447- 





'T-x . 





 ^vO'X^^v ^^^^. 



r  r.^^Y\^.^ 





A^' . -^H ' - — . _\. . - ^ -. ,, 







/' V 





Section ot unnijected liver, showing cords of hepatic cells between capillary blood-vessels. X 450. 



their nucleus. Such cells, according to Reinke,^ soon undergo division and pro- 

 duce the double nucleated elements constantly encountered in sections of normal 

 liver. Centrosomes have also been observed in resting hepatic cells. Particles of 

 glycogen, minute oil droplets, and granules of bile-pigment are more or less constant 

 constituents of these elements. The fat- containing cells are most numerous at the 

 periphery of the lobule, those enclosing pigment particles near the centre. 



The Bile-Capillaries. -^These minute canals, representing the lumina of 

 ordinary tubular glands, form a net-work of intercommunicating channels throughout 

 the lobule closely related to the liver-cells. Whereas in the usual arrangement a 

 single surface of several gland-cells borders the lumen, in the exceptional case of the 

 liver the excretory channels are bounded by the opposed surfaces of only two cells, 

 the bile-capillary occupying but a small part of the surfaces, on each of which it 

 models a narrow, centrally situated groove. Moreover, not only a single surface 

 of the hepatic cell takes part in bounding the canaliculi, but the latter are found 

 between all surfaces where two liver-cells are directly in contact, so that each hepatic 

 element comes into direct relation with a number of bile-capillaries. The latter, 



^ Verhandlung d. Anatom. Gesellschaft, 1898. 



