The Ampulla of Vater. 127 



greater the lesser ; hence, if the names are retained they can 

 merely indicate that there are two of a kind and one is larger 

 than the other, without any regard to absolute or relative posi- 

 tion. The pancreatic duct opening with the ductus choledo- 

 chus, is called, in man, the duct of Wirsung or the principal 

 duct, and the other the accessory or minor (i, 384 ; 14, 793 ; 

 22 ; 51 ; 23,497; 25 ; 27). It not unfrequently happens that the 

 duct opening with the ductus choledochus is smaller than the 

 one opening independently, which is now, from its size, called 

 the principal duct, and the other is called the accessory duct, 

 for the same reason (i, 386 and Plate XIII., Figs. I., II.,) (6, 172). 

 Take, for example, this remark of Dalton's ; *' Even in the 

 human subject, as shown by Bernard, Kolliker, and Sappey, 

 there is often a small accessory duct opening into the intestine, 

 sometimes above (nearer the pylorus) and sometimes below 

 (farther from the pylorus) the situation of the principal one " 

 (6, 172). If one has in mind the statements of Salter (27, 85) 

 and Owen (23, 497), that- the accessory or smaller duct opens 

 independently into the intestine at a point farther from the 

 pylorus than the common opening of the ductus choledochus 

 and duct of Wirsung, he might properly suppose that the 

 duct opening with the bile-duct remained constantly the larger, 

 while the small duct opened independently into the intestine, 

 sometimes nearer the pylorus and sometimes farther from it. 

 Taking the statements of Bernard (i, 384) and Santorini 

 (28 ; I, 383, also 8 and 18) that the duct opening independ- 

 ently, or the accessory duct, is nearer the pylorus than the one 

 opening with the ductus choledochus, the alternative is left to 

 suppose that the duct opening with the ductus choledochus 

 may sometimes be smaller than the other, and for that reason 

 be called the accessory duct, while the other, from its size, is 

 now called the principal duct. The figure added by Dalton 

 (6, 172, Fig. 46) showed this last to be the meaning. 



If we turn to comparative anatomy, the confusion is nearly as 

 great, for in dogs the larger duct opens independently at a 

 considerable distance farther from the pylorus than the ductus 

 choledochus, and the smaller opens also on the same side, 

 but very close indeed to the ductus choledochus (i). 

 In the cat the case is reversed, the larger duct opening 

 into the ampulla of Vater, and the smaller one inde- 

 pendly and farther from the pylorus (PI. XII., Fig. I., i and 2). 



