rs ' 
umbilical vein directly backwards to the vena cava. At the time of birth the ductus 
venosus and umbilical vein cease to carry blood, their cavities become obliterated, and they 
degenerate into fibrous cords. 
THE -LIVER. 1067 
Physical Characters of the Liver.—The liver is a compact mass, moderately 
firm to the touch; it is plant, but not tough, and is easily lacerated. Its torn 
surface presents a granular appearance, due to the fact that it is made up of small 
lobules about the size of a pin’s head (th to ,th of an inch, 1 to2 mm.).. These 
little lobules also give its exterior a characteristic finely-mottled appearance. — Its 
colour is reddish brown, and its specific gravity varies from 1:05 to 1:06. 
In the Child —The liver of the child differs from that of the adult, in being rela- 
tively larger—,,th of the body weight at birth as against ,),th or ,jth in the 
adult—in occupying more of the abdominal cavity, and in the fact that its two 
lobes are more nearly equal in size, the pro- 
portion being as two to one at birth and as 
four to one in the adult. 
Variations in Size, Form, and Position.—Few 
organs will be found to vary more in size in different 
bodies than the liver; these variations, however, are 
very frequently to be looked upon as pathological. 
But even normal, healthy livers vary in weight from 
48 to 58 ounces in the adult male, and’ from 40 to 50 
ounces in the female. 
Variations in form and position doubtlessly take 
place physiologically, as a result of the conditions 
of fulness or emptiness of the adjacent viscera ; for, 
though the liver, hke the other solid abdominal 
organs, has an intrinsic shape of its own, this is 
capable of modification within certain limits by the 
varying pressure of the surrounding parts. Thus, 
ereat distension of the stomach, or of a portion of 
the transverse colon lying in the stomach chamber, | 
pushes the liver over to the right, so that it may 
hardly reach the middle line, and at the same time it oh 
increases its vertical depth. On the other hand, a 
distended state of the small intestines, with a con- 
tracted stomach and colon, may have the opposite Fie. 717.—THr AppoMiNnAL anD_THoRAcTC 
Umbilical vein 
- Umbilical cord 
Urachus 
Hypogastric 
artery 
Bladder 
effect, flattening it from below upwards and enlarg- VISCERA OF A FIvE-MontTHs Fatus. 
ing it in the transverse direction. The large liver and the large size of its left lobe, 
Variations in form and position due to mal- at this age, should be noted. 
formations of the thoracic framework, either con- 
genital or acquired, are very common, particularly in females as a result of tight lacing, which 
carries in the lower ribs. Sometimes in these cases the constriction of the waist hes chiefly 
below the liver. The organ is then forced up against the diaphragm, filling its whole vault, and 
extending across to the left abdominal wall, where its left margin may le in the interval 
between the diaphragm and the spleen. But more commonly it would seem that the liver is 
caught by the constriction : its upper part is then closely pressed into the vault of the diaphragm, 
which, owing to the narrowing of the thorax, is unable to accommodate the whole organ, so 
that its lower part is crushed down for a considerable distance into the umbilical zone of the 
abdomen (Fig. 678, p. 1006), particularly on the right side. Often, too, a wide, tongue-like 
process (the so-called “ Riedel’s lobe”) descends from the lower margin, external to the gall- 
bladder. This process, which when very large may reach to the iliac crest, is sometimes found 
in men, although more common in women, and is able to be mistaken for a tumour. A some- 
what similar process occasionally descends from the left lobe. 
Again, in apparently healthy bodies the ver may extend up on the right side almost to the 
fourth rib; whilst in other cases it may be as low as the sixth rib, or even lower. Nor is it 
rare—particularly in females—to find the lower border projecting two or three inches (5:0 to 75 
em.) below the margin of the thorax on the right side (Fig. 678, p. 1006). 
Reference should be made here to certain grooves often seen on the liver. Some of these are 
found running obliquely low down at the right side where the liver is in contact with the ribs ; 
they are particularly common in females, and are due to the pressure of the ribs resulting from 
tight lacing. Grooves of a different kind are found at the upper part of the parietal surface, 
where the liver is in contact with the diaphragm ; these usually run radially, that, is in the 
direction of the muscular fibres of the diaphragm, and are apparently produced by a wrinkling, 
or irregular contraction, of the diaphragm. At least, ridges of the diaphragm are found lying in 
the grooves, and these ridges or wrinkles would seem to be responsible for the production of the 
erooves. 
Finally, the liver may present certain congenital irregularities in the direction of additional 
fissures and lobes, which reproduce the conditions found in the higher apes, and are very 
