The coverings of the liver are twofold, a scrolls investment, which is obtained from the perito neum, and a proper fibrous capsule derived from ;he capsule of Glisson. The peritoneum encloses the whole of the liver with the excep tion of that part of the posterior border which constitutes the oval space (Pr. 32, 11, fig. 33, 15,) and is surrounded by the coronary ligament, of the fossa for the gall-bladder, the fissure for the vena cava, and the transverse fissure. The proper capsule is most apparent upon those parts of the organ which are left uncovered by the peritoneum, particularly on the oval space upon its posterior border.
The color of the liver varies considerably, both with the period of life and with the greater or smaller proportion of blood or bile contained within its vessels. Thus in infancy it presents a light red colour, which deepens into a reddish brown in the adult, and increases in depth of shade with the age of the subject. If the individual have died from hmmorrhage, the liver appears bleached and presents a yel lowish grey tint ; if from general congestion, it may assume a chocolate or purplish brown or a slate colour, and if from obstruction to the bile-ducts, a variable shade of yellow. Its texture is firm and dense, but extremely fra gile, the fracture presenting a granular appear ance.
The dimensions of the liver are very consi derable, as may be inferred by recollecting that this is the largest organ in the body. Through the longest diameter from the extremity of the right to the edge of the left lobe, it measures about twelve inches; from before backwards, through the transverse diameter of the right lobe, about seven inches, and through the thick est part of the right lobe, in a vertical di rection, about four inches. These measure ments, however, can only be received as an approximation to the average, for the size of the organ varies in different individuals; thus it is larger in males than in females, and is more bulky in persons of sedentary habits than in those who are robust and active. Its weight is about five pounds ; its relative weight to the entire body, as 1 to 36 ; and the specific gra vity one half heavier than water.
Chemical analysis of the human liver has shewn that in 100 parts, there are, of Water 61.79 Solid matters 38.21 Of 100 parts of the solid matters, 71.18 are soluble in water, hot or cold, or 1 alcohol; and consist of, osmazome, 1 stearine, elaine, resin, oleic and margaric acids, gelatine, and sali vine.
1 28.72 are insoluble.
2.034 are salts; viz. chloruret, phosphate of potash, phosphate of lime, and oxide of iron.
Bullocks' liver, analysed by Braconnot, is, according to Berzelius, analogous to the pre I.
ceding, the differences being dependent solely 1 upon a difference of manipulation. 100 parts ? contain, 55.50 water.
44.50 solid matters, composed of, Illi Vessels and membranes ..18.94 Soluble matters 25.56 100 parts of the pulp of liver contained, 58.64 water.
20.19 dry albumen.
6.07 matter very soluble in water ; slight ly in alcohol ; containing little 3.89 fat. 0.64 chloruret of potash. 0.47 phosphate of lime containing iron. 0.10 salt of potash combined with a combustible acid. Varieties in the liver may be referred to one if two heads—varieties in form, and varieties in 9osition. Varieties in form occasionally occur, but hey are more rare in the liver than in almost other organ of the body. I have seen the lobe so small as to appear but a mere ap iendage to the right, being connected to it only ')y a thin and narrow isthmus. Cruveiihier re ords an instance in which the left lobe was attached to the right merely by a vascular pe dicle about half an inch in length; the extre mity of the lobe being adherent to the upper part of the spleen. Deep and narrow grooves are occasionally seen upon the convex surface of the right lobe running in an antero-posterior direction ; they correspond with projecting fasci culi of the diaphragm, and occur generally in women who have laced tightly. This surface is also marked frequently in females with deep channels, which are formed by the pressure of the ribs, and are also the result of tight lacing. The liver is sometimes' constricted in the middle from this cause -and a dense fibrous band, produced by thickening of the fibrous capsule, extends around it like a belt. The lobes are occasionally divided by deep fissures into several additional lobes ; the liver in this case presents a character which is normal amongst the lower animals. In a few in stances the fossa for the gall-bladder has been found excavated so deeply as to render the fundus of the sac apparent through an open ing on the upper surface of the liver, a pecu liarity which is also normal amongst some of the lower tribes of animals.