LIVER 



173 



tiver. The primary rudiment of the liver takes the form of a diverticulum 

 of the ventral wall of the gut immediately behind the stomach. The diverticulum 

 first appears as a wide and elongated groove, which becomes closed, and extends 



X300 



FIG. 218. SECTION OF THE DEVELOPING LIVER, TO SHOW HOW THE HEPATIC CYLINDERS ENCROACH 

 ON THE LUMINA OF THE SINUS-LIKE VEINS TO BREAK THEM UP ULTIMATELY INTO CAPILLARY-LIKE 



CHANNELS CALLED SINUSOIDS. (Miliot.) 



k.c., hepatic cylinders ; ai, sinusoids. 



forwards into the substance of the septum transversum (fig. 217). From the fore- 

 part of the diverticulum cells are rapidly budded off from the epithelium to form 

 the parenchyma of the gland. The hinder part of the groove does not share in 



FIG. 219. SECTION OP THE DEVELOPING LIVER AT A LATER STAGE THAN IN FIG. 218, TO SHOW THE 

 MANNER IN WHICH THE HEPATIC CYLINDERS COME TO FORM A TRABECULAR FRAMEWORK OF 

 PARENCHYMA WITH A NETWORK OF SINUSOIDS IN ITS MESHES. (Minot.) 



Ji.c., hepatic cylinders ; si, sinusoids. 



this proliferation, and persists as the bile-duct. Before being closed it gives off a 

 second ventral pouch, which is ultimately converted into the gall-bladder. The 

 mass of cells budded off from the wall of the tubular diverticulum invades the 



