THE VENTRAL PANCREAS 



391 



or outpocketed so that, to a certain extent, a connection is formed 



between these buds In the next stage we see a 



single ventral pancreas which has arisen through the confluence 

 of the two ventral pancreatic buds " 



Helly (1901), after studying rabbit, rat, guinea-pig and cat 

 embryos, concluded that the ventral pancreas is paired, but that 

 its parts do not fuse. He writes as follows: 



"The ventral buds develop from the lateral walls of the ductus 

 choledochus. They arise quite separate from one another; in 





'"% 





Figs. 1 and 2 Transverse sections of a pig embryo of 3.6 mm. (Harvard Embrj-o- 

 logical Collection, Series 1406, Sections 119 and 128). X 75 diam. 



Fig. 3 Transverse section of a pig embryo of 4.5 mm. (H. E. C, Ser. 1404, 

 Sect. 104). X 75 diam. a, h, buds which give rise to the ventral pancreas, P. v. 

 c, d, plates which give rise to the dorsal pancreas, P. d. x, lateral proliferation. 



no case could I observe a fusion between them. The left ventral 

 bud undergoes degeneration." 



In the Harvard Collection, there is rabbit embryo of eleven 

 and one-half days (5.6 mm.) which appears to accord with Helly's 

 description, since the median mass is directly continuous with a 

 swelling on the right side of the bile duct, and the swelling on the 

 left side is smaller and perhaps free from the ventral pancreas. 

 But in two other rabbits of the same age, this relation is not seen ; 

 in them, the ventral pancreas appears to be exactly median, and 

 it encroaches little, if at all, upon the sides of the bile duct. More- 



