568 



STORAGE OF GLYCOGEN. 



[BOOK ii. 



(25), by which as we have seen the hepatic cells are markedly 

 affected, the liver is found to be free from glycogen, and the 

 hepatic cells to be extremely small (cf. Fig. 106 c), only half 

 the size or even less, of those of the well-fed frog, but otherwise 

 much like the cells in a frog fed on proteid material. 



362. In the mammal changes in the hepatic cells similar 

 to those just described as occurring in the frog have also been 



observed. When the animal is fed on 

 a diet rich in carbohydrates, and when 

 therefore as we have seen the liver 

 abounds in glycogen, the hepatic cells 

 (Fig. 107) are larger (so large that they 

 have by some authors been described 

 as compressing the lobular capillaries) 

 and loaded with the same refractive 

 hyaline material staining port-wine red 

 with iodine. When this material, which 

 is disposed more centrally in the cell 

 than is the case in the frog, is dissolved 

 out a coarse open network of cell-sub- 

 stance is displayed. We may add that 

 animal thus fed the whole liver 



FIG. 107. SECTION OP 

 MAMMALIAN LIVER RICH IN 

 GLYCOGEN. (Langley.) 



Osmic acid specimen, gly- 

 cogen not dissolved out. 



in an 



is very large and as it were swollen ; it is also soft and tears 

 easily. 



In an animal fed on proteids alone, for instance on fibrin, the 

 liver frequently contains some glycogen and the hepatic cells 

 contain a small quantity of hyaline glycogenic material. As 

 in the corresponding case in the frog, the cells are compara- 

 tively small, and the cell-substance appears finely and uniformly 

 granular. 



In a starved mammal, the liver is small, dense to the touch 

 and tough ; it contains a trace only of glycogen or none at 

 all; the cells (Fig. 108) are small, as it were shrunken, and 



the cell-substance, which gives no port- 

 wine reaction, or a mere trace only, 

 with iodine, is still more finely granu- 

 lar. 



363. The microscopic appearances 

 just described shew, and indeed general 

 considerations lead us to the same con- 

 clusion, that the processes taking place 

 in a hepatic cell are very complex. In 

 the first place, the constituents of bile 



FIG. los. SECTION OF MAM- are being formed and discharged into 

 "TT'LE" OR K N R O C G^COGE N N Q the bile passages after the fashion of 

 (Langiey.) an ordinary secreting gland. In the 



Osmic aid specimen. The second place, a formation of glycogen is 



granules are not well pre- , , iri 



served in some of the cells. also taking place, and we shall have pres- 



