THE ALIMENTARY TRACT, SPLEEN, AND MESENTERIES 267 

 (q.v.), and has a slight median cleft anteriorly where the ventral, or 

 sub-hepatic, mesentery joins the lig. hepato-entericum. 



There is a relatively large gall-bladder (gl.b.) lying just dorsal to 

 the right lobe of the liver. In order to distinguish the details of the 

 bile-ducts it is necessary to dissect away some portion of the liver 

 tissue since they are completely embedded therein, with the excep- 

 tion of the common bile-duct itself which is embedded in the 

 ventral pancreas. 



Three main bile-ducts emerge from the liver (see Fig. 76). On 

 the extreme right — left as viewed — is the hepato-cystic duct (d. h-c.) 

 which bears the gall-bladder as a lateral expansion of its walls, and 

 afterwards becomes the cystic duct (d.cy.), which is joined almost 

 immediately by the Jirst hepatic duct (d.h.'). The latter is separated 

 from the former by the ventral hepatic artery. The second hepatic duct 

 (d.h.") enters farther down, within the pancreas, so as to produce 

 a very short common bile-duct (d.c.) into which the ducts of the ventral 

 pancreas also discharge. 



2. The Pancreas. 



^he pancreas (pan.) is roughly triangular in shape, and lies rather 

 to the dorsal side of the duodenum, between it and the stomach. As 

 Goppert (1891) and Choronshitsky (1900) have shown, the adult 

 pancreas is a composite gland, representing three outgrowths from 

 the embryonic gut, namely, two ventral and one dorsal. As already 

 stated, the two ventral pancreata discharge their secretion into the 

 common bile-duct, while the dorsal pancreas discharges by a separate 

 duct directly into the duodenum. The pancreatic ducts are by no 

 means easy to see by direct observation, but may be readily demon- 

 strated by cutting a series of microtome sections of the duodenum. 

 The three lobes of the embryonic pancreas become indistinguishably 

 fused in the adult into a single mass. 



THE SPLEEN 



The spleen (sp.) is not strictly an appendage of the gut, but, since 

 it is suspended from the left dorso-lateral wall of the stomach by the 

 lig. gastro-lienale, and in part shares its blood-supply, it may con- 

 veniently be considered here. It is a comparatively thin, elongated 

 ovoid body, some 10-15 mm. long by 4-4^ mm. broad. It is deep 

 red in colour in the fresh condition. Choronshitsky holds that it is 

 purely mesodermal in origin, while functionally it is of course a 

 blood gland. 



