ANATOMY OF B A3AEN OPTEE A EOSTEATA. 
249 
The remaining portion of the small intestine extended from the duodenum to the 
caecum ; it measured in length 80 feet, and in circumference from 4 to 5^ inches ; in its 
course four remarkable dilatations were observable placed at variable distances from 
each other ; some of these measured 10 inches in circumference and about 4 inches in 
length. Of the three divisions of the small intestines the duodenum was the largest 
in calibre, the jejunum the smallest, and the ilium intermediate in size. 
The mesenteric vessels were very large and numerous, and many lacteals and glands 
clustered about the root of the mesentery, more particularly at the point of junction 
between the ilium and caecum ; a chain of glands lay in the concavity of the terminal 
coil of the former, enclosed in the layers of the mesocsecal fold of peritoneum, each of 
which was about the shape of a kidney bean ; similar glands were traceable upwards, 
but less distinctly, and at greater intervals along the entire length of the ilium. 
The intestinal wall consisted of four coats. First, a peritoneal ; second, a longitudinal 
series of muscular fibres ; third, a series of circular fibres, which in the regions of the 
dilatations or pouches before mentioned were thinner and more expanded than else- 
where ; and fourth and lastly, the mucous lining, which was thrown into five or six folds 
or plications, which in the upper portion of the intestine were arranged principally in a 
longitudinal direction at irregular intervals round its wall ; these longitudinal folds were 
here and there connected by transverse ones, which were best marked along the concave 
or attached margin of the gut, and projected from its mucous surface for the depth of 
about 3 lines. 
The depth of the primary or longitudinal plicae varied from 6 to 9 lines ; sometimes, 
but rarely, they joined each other at an acute angle, and wherever this occurred they 
enclosed a long irregular lozenge- shaped space ; in the intervals of these folds the 
mucous membrane was perfectly smooth, particularly on the convex wall of the intestine ; 
in the other portions, especially on the sides of the jejunum, numerous patches of mucous 
follicles were distributed. In the ilium transverse folds (valvulae conniventes) took the 
place of the longitudinal ones and were increased in size. The glands of Peter occurred, 
both solitary and in scattered patches, all through the ilium. 
On laying open one of the before-mentioned dilatations, the mucous membrane lining 
it was seen to be arranged in the form of crescentic folds at each of its extremities, the 
concavities of the folds being placed in opposite directions, and the portion of the wall of 
the gut intervening between them was sacculated and extremely thin, being but scantily 
covered by the muscular coat ; this was most observable at the fundus of each pouch, 
where the wall of the intestine seemed only to consist of the serous and mucous coats. 
In the parietes of the jejunum, at its gastric extremity, a number of hard tubercular 
bodies were situated, which to the' touch conveyed the sensation of their being lym- 
phatic glands ; these, on opening into the intestine, presented on its mucous surface the 
appearance of somewhat bluntish conical papillae, which were perforated at their apices 
by small orifices, one on each eminence, capable of admitting the head of a small pin. 
These apertures led into tortuous canals enclosed in the coats of the intestine, and were 
MDCCCLXVIII. 2 N 
