48 PROFESSOR A. BIRMINGHAM. 



the appearance of a raised map of a very mountainous district, 

 in which the chief chains run irregular courses, and are joined 

 to one another by connecting ridges. 



Brunners glands form an almost continuous layer of little 

 rounded or flattened masses (of a reddish-grey colour, varying 

 in size from one-fiftieth to one-twelfth of an inch in diameter) 

 in the submucosa of the duodenum, as far as the opening of the 

 bile-duct ; beyond this, they can, however, be easily traced, 

 diminishing progressively, and they disappear altogether near the 

 duodeno-jejunal flexure. 



The mesentery rarely measures more than 6 inches from its 

 posterior attachment to the intestine directly opposite. Treves 

 and Lockwood give the length of the mesentery as 8 or 9 inches ; 

 this measurement must, I imagine, have been taken obliquely, 

 perhaps from the upper part of the posterior to the lower part 

 of the intestinal attachment. 



Whilst the root of the mesentery pursues at its attachment 

 an almost straight line from one end to the other, if cut across 

 a very short distance from the abdominal wall, it will here be 

 found to form a wavy or undulating line. Further out still, 

 this becomes more and more marked, and finally, if the bowel be 

 removed by cutting through the mesentery close to its attach- 

 ment to the intestinal wall, it will be seen that its free edge 

 is not only undulating, but is frilled or plaited to an extreme 

 degree. When shown in this way it is found that the plaiting 

 or folding is not quite indiscriminate, but that the main folds, 

 of which there are usually six, run alternately to the right and 

 left. As a rule, the first fold runs to the left from the duodeno- 

 jejunal flexure, and goes to a coil of jejunum, which lies under 

 the transverse mesocolon, and helps to support the stomach. 

 (This coil has been already referred to.) The second fold 

 passes to the right, the third to the left, and so on up to the 

 fifth and sixth, which are usually small. From the margins of 

 these primary folds, secondary folds project in all directions, and 

 from these again even a third series may be formed. 



This order is, of course, by no means constant, but if the 

 intestine be removed from a hardened body in the way suggested, 

 without disturbing the mesentery, it will be found to be arranged 

 with more or less regularity on some such plan as that indicated. 



