390 FREDERIC T. LEWIS 



has been observed in the rabbit, rat, guinea-pig and cat by Helly, 

 and has been figured by Debeyre in a human embryo of 4.5 mm. 

 In Debeyre's specimen, however, the buds are ill-defined. 



In a pig embryo of 4.5 mm. (fig. 3), the ventral pancreas is a 

 median mass of cells in the angle between the ductus choledochus 

 and the intestine. On the left side, this mass connects with a 

 lateral outgrowth (x) which extends through six sections, terminat- 

 ing below in the section figured. On the right side, there is a 

 corresponding outgrowth extending through four sections, but 

 it is separated by one section from the median mass. If these 

 lateral outgrowths correspond to the buds shown in fig. 1, it 

 appears that the median mass has arisen in the interval between 

 the buds, on the lower or posterior side of the ductus choledochus. 

 Frequently the median mass has been described as continuing 

 upward on either side of the bile-duct, producing symmetrical 

 lateral swellings. This condition was found by Jankelowitz 

 in a human embryo of 4.9 mm. It was observed by Brachet in 

 rabbit embryos of ten and one-half to eleven and one-half days 

 and he described it as follows : 



''The ventral pancreas is formed at the expense of a semicir- 

 cular fold embracing the posterior circumference of the ductus 

 choledochus and the adjacent parts of its lateral walls .... 

 It really represents two outgrowths which have fused." 



Hammar, in the following year (1897), described the ventral 

 pancreas of the rabbit in the same way. He wrote: 



"It appears on the ductus choledochus as a thickening or out- 

 pocketing which semicircularly embraces the caudal and lateral 

 surfaces of the duct. As soon as it projects freely, it appears as 

 a single caudally directed outgrowth of the ductus choledochus." 

 But he concluded that the description of the ventral pancreas as 

 paired was "not applicable to the rabbit, dog and probably 

 other mammals." 



Choronshitzky (1900) described this condition in sheep embryos 

 in almost the same terms, yet he regarded the ventral pancreas 

 as paired. 



"The caudal or ventral wall of the ductus choledochus, between 

 the two ventral pancreatic buds, may be semicircularly thickened 



