488 FREDERIC T. LEWIS 



to find that water or salt-solution passed rapidly through the 

 full stomach of a dog, without mixing with the gastric contents. 



Gyllenskoeld (1862) states that the oblique fibers extend only 

 to the pars pylorica, and not to the pylorus as described by Willis. 

 This has been confirmed by Kaufmann (1907). He found that 

 there is no sphincter of circular fibers separating the pars cardiaca 

 from the pars pylorica, but that the furrow between them has a 

 special structure, since it is the place where the oblique fibers 

 terminate and interlock with the circular fibers. 



Hasse and Strecker (1905) have named the folds which bound 

 the gastric canal the 'plica hepatica' and 'plica aortica' respec- 

 tively, and state that they are connected with one another by the 

 'plica cardiaca' which passes around the cardia, projecting into 

 the stomach beneath the incisura cardiaca. According to Hasse 

 and Strecker the plica cardiaca does not form a valve for the 

 cardia, as Braune (1875) thought possible from the result of experi- 

 ments on a cadaver. The hepatic, cardiac and aortic plicae 

 together form a U-shaped structure, across the open end of which 

 is the 'plica angularis.' This is beneath the incisura angularis, 

 at the beginning of the pars pylorica. 



Waldeyer, who describes the channel from cardia to pars 

 pylorica as the ' Magenstrasse' (1908), considers that its formation 

 depends upon the oblique muscles, rather than upon folds which 

 arise in relation with adjacent organs. In the following pages 

 evidence will be offered to show that the gastric canal is a distinct 

 epithelial structure, arising independently both of the muscle and 

 the surrounding organs. 



There remain to be considered two structures which are beyond 

 the limits of the stomach — the 'antrum duodenale' and the 'antrum 

 cardiacum.' 



Retzius (1857) states that the beginning of the duodenum is 

 often specially rounded, not only in man, but in a large propor- 

 tion of mammals; in dolphins it has been considered a part of the 

 stomach. Owen (1868) remarks that in all Artiodactyles the 

 duodenum is dilated at its commencement; it there forms a dis- 

 tinct pouch in the camel. For this pouch Retzius proposed the 



