324 DRS HEPBURN AND WATERSTON ON THE 



mucous membrane of the second and subsequent compartments. Whether these nodules 

 communicate directly with the lumen of the intestine we cannot say, but we have not 

 found any trace of surface epithelium superficial to these nodules in any part of the 

 alimentary canal, where they occur embedded in the mucous membrane. There is 

 plentiful evidence that these nodules push their way entirely through the stratum of 

 tubular and intertubular tissue of which the mucous membrane consists. If they are 

 covered over by a layer of surface cells, as is generally supposed, there are certainly 

 no glandular structures between them and the lumen of the canal. In their whole 

 structure they present a remarkable similarity to the faucial tonsils of man, and they 

 may serve a similar purpose. 



The Pylorus. — The pyloric orifice was a tightly constricted passage which, with 

 some pressure, would admit a rod 5 mms. in diameter. It was situated in the middle 

 of a projection somewhat like an exaggerated nipple. The actual orifice was found 

 on the summit of this nipple, which was directed into the interior of the compartment 

 backwards and to the right side. 



Every one of these constricted passages was placed as if with the definite object 

 of making the onward progress of the contents as difficult as possible, and only 

 attainable after the most complete circuit of the compartment. The length of this 

 canal was rather more than half an inch (16 mms.). In its general arrangement and 

 appearance it resembled the canal which formed the passage of communication from the 

 second to the third compartments. Still no one has ever proposed that the pyloric 

 passage should be adduced as a separate chamber, and so we regard Jungklaus' state- 

 ment upon the third chamber as an error in homology. 



The Duodenum. — Beyond the pylorus, the intestine commenced with a marked 

 dilatation, whose diameter at first resembled that of the adjoining part of the stomach. 

 Very soon, however, it slightly increased in size, but after a course of two and a half 

 inches (6'5 cms.), it suddenly dwindled and assumed the general characters of the 

 remainder of the intestine. 



Immediately before this dilatation became reduced to the proportions of the ordinary 

 bowel, it received the bile-duct which penetrated its dorsal surface. Further, the 

 pancreas was closely applied to this portion of the canal, but the pancreatic duct formed 

 a tributary of the bile-duct, and so did not show a separate opening through the wall. 

 This disposition of the pancreatic ducts was not surprising, since the bile-duct passed 

 through, and was therefore surrounded by the head of the pancreas. From this 

 disposition of these important ducts we are justified in regarding this section of the 

 canal as the duodenum, which therefore corresponds to what are called the first and 

 second parts of the human duodenum. 



On being opened, the duodenum was seen to be lined by a mucous membrane con- 

 siderably darker in colour than those which had lined the preceding compartments of the 

 stomach. Whether this colour should be attributed to staining by bile we cannot say, 

 as there was no gall-bladder, and therefore we saw no bile. It was thrown into promi- 



