THE ORGANS OF THE INNER GERM-LAYER 331 



into the left half of the peritoneal cavity, whereas the liver grows out 

 into the right ha ] f more than into the left. In consequence of the 

 formation of the liver and the lesser omentum, the greater omentum, 

 produced by the torsion of the stomach, receives an addition, which 

 is designated as its antechamber (atrium bursse omentalis). For there 

 comes to be associated with the greater omentum that part of the 

 body-cavity which lies behind the liver and lesser omentum , and which 

 in the adult possesses, as is well known, only a narrow entrance (the 

 foramen of WINSLOW) lying below the ligamentum hepato-duodenale. 



Concerning the development of the coronary ligament, see a subsequent part 

 which treats of the diaphragm. 



As far as regards the conditions of form and size which the liver 

 presents up to the time of birth, there are two points which are 

 worthy of attention : first, the liver early acquires a very extra- 

 ordinary size ; secondly, its two lobes are developed at first quite 

 symmetrically. In the third month it nearly fills the whole body- 

 cavity ; its free sharp margin on which a deep incision between the 

 two lobes is observable reaches down almost to the inguinal region, 

 leaving here only a small space free, in which, upon opening the body- 

 cavity, loops of the small intestine are to be seen. It is a very vas- 

 cular organ, for a great part of the blood returning from the placenta 

 to the heart passes through it. At this time the secretion of bile 

 begins, although only to a slight extent. This increases in the second 

 half of pregnancy. In consequence of this the intestine gradually 

 becomes filled with a brownish-black mass, the meconium. This is 

 a mixture of bile with mucus and detached epithelial cells of the 

 intestine, to which is added amniotic water with flakes of epidermis 

 and hairs that have been swallowed. After birth the meconium is 

 accumulated in the large intestine, from which it is soon afterwards 

 eliminated. 



In the second half of pregnancy the growth of the two lobes of 

 the liver becomes unequal, and the left is surpassed more and more in 

 size by the right. Before birth the lower margin of the liver projects 

 downward for some distance beyond the costal cartilages, almost to 

 the umbilicus. After birth it diminishes rapidly in size and weight, 

 in consequence of the change in the circulation produced by the pro- 

 cess of respiration. For the stream of blood which during embryonic 

 life has branched off from the umbilical vein into the liver now ceases. 

 During the growth of the body the liver also increases in size still 

 further, but less than the body .taken as a whole, so that its relative 

 weight is constai tly undergoing reduction. 



