Cited by T.W. Shore and J.H. Lewis, 'On the Structure of the Vertebrate Liver', Journal of Physiology 10 (5) (1889), pp. 408-432.
Description:

Explanation of Plate XXVIII (figs. 5-8):

'Fig. 5. Section of the liver of Coecilia. (x 400 diam.)

a. A blood capillary.

b. Section of a liver tubule.

c. Lumina of liver tubules cut transversely and lougitudinally.

Fig. 6. Section of the liver of the Newt. (x 400 diam.)

a. Spaces for capillary blood-vessels.

b. Liver cells.

c. Bile capillaries.

d. Mass of brown pigment.

Fig. 7. Section of the liver of the Tortoise. (x 400 diam.)

a. Blood capillary containing clotted blood.

b. Endothelial wall of a blood capillary.

c. Inner granular zone of the liver cells.

d. Outer clear zone of the liver cells.

Fig. 8. Section of the liver of a young Chick. (x 420 diam.)

a. Capillary blood-vessel.

b. Endothelial wall of blood capillary.

c. Liver tubules cut transversely.

d. Lumen of a liver tubule.' (427)

 

Fig. 5 in text:

'The liver of a Coecilian (Plate XXVIII. Fig. 5) is a good example of a well-developed tubular liver. In this creature, the liver consists of a series of foliaceous lobes, each three or four millimetres across, arranged in an imbricated manner along one side of a main duct, which sometimes is over two inches long. The cells are clear, or very faintly granular, with their nuclei arranged peripherally. There are five rows of cells lining the tubules, whose diameter varies considerably, the average size being 40µ. The lumen, though small, is very distinct, and there is no basement membrane. The tubules are arranged in elongated meshes, are much convoluted, and the anastomoses are not very abundant. The relative diameter of blood capillaries when compared with that of the tubules is greater than in the case of the frog.' (415)

 

Fig. 6 in text:

'The newt's liver is essentially a parenchyma of large cells, permeated by a network of fine blood capillaries and drained by a reticulum of minute bile channels, which lie usually at the angles where three or fouir cells meet, and so arranged that each cell has on somie side of it a blood capillary and is connected at one point, at least, of its surface with a bile channel (Plate XXVIII. Fig. 6). Scattered through the organ are numerous rounded masses of a dark brown pigment, of irregular sizes, but having an average diameter of about 25µ.' (416-417)

'There is nothing in the knownw history of the development of the liver which opposes the idea that the gland may have arisen from a solid mass of hypoblast cells formed at the extremity of the primitive hepatic diverticulum and which growing and forcing its way into the surrounding mesoblast, becomes itself interpenetrated by ingrowing mesoblast cells. By the development of these latter into blood capillaries the hypoblastic cell mass would become broken up into a network of solid anastomosing rods, in which secretion channels would subsequiently form, and which would be more or less fine according to the completeness with which the ingrowth of developing blood-vessels took place...

An examination of the liver of the types we have described in the light of our hypothesis will show that all the appearances can be explained by it. We can find no other satisfactory interpretation of the arrangement seen in the liver of the lamprey (Plate XXVII. Fig. 1). A comparison of a section of the eel's liver with that of a mammal (Plate XXVII. Fig. 2 and Plate XXIX, Fig. 12) shows clearly that a more intimate subdivision by capillaries in the case of the latter would account for the differences, and at the same time it is seen that the relative magnitude of the blood capillaries in the two cases is very different - those of the eel can scarcely be called "capillaries". That this is the true difference in the two cases is clear from a comparison of a section of the liver of an embryo mammal with that of the adult and with that of the eel (Plate XXVII. Fig. 2, and Plate XXIX., Figs. 9 and 12). On examining a section of the liver of the newt, the appearances seen, making allowance for the different sizes of the cells and smaller details, are more like those of the mammal's liver than that of any other of our types - (Plate XXVIII. Fig. 6) - There has been in this case a penetration of the mass of liver cells sufficiently intimate to have left but three or four rows of cells to form the tubules, and at the same time the total vascularity of the organ, as shown by the size of the blood spaces, is not so great as in the case of the eel or the mammal.' (423-424)