236 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



siicli larg^ specimens was that injury was so easily done to tliem^ 

 thus apparently detracting from their value. Important evi- 

 dence, however, was furnished in this way as will appear later. 



!N^early all the specimens of the mesentery were taken from 

 that of the small intestine, because much greater delicacy in 

 handling the material was possible here. Some preparations 

 were made from the meso-colon ; but as these were found similar 

 in all respects to those from the mesentery of the small intes- 

 tine, and as the danger of injury was much greater owing to 

 its situation, most of the work was done on the mesentery of 

 the small intestine. 



The Peritoneal Epithelium. All of the epithelium of the 

 peritoneal cavity which was studied consisted of a simple layer 

 of flat, polygonal cells, bounded by rather relaxed, wavy lines» 

 PL 14, fig. 1, 2, 3. The variation in the size and form of 

 the individual cells in the same region of the peritoneal cavity 

 was slight, but between different regions was quite noticeable. 

 In general it may be said that the cells of the epithelium of 

 the mesentery were the most uniform both in size and shape. 

 They were larger than those of the central tendon and suspen- 

 sory ligament, but smaller than those of the omentum. The 

 cells of the latter were the largest and most irregular found; 

 they were narrower in proportion to their length and were 

 bounded by more undulatory and distinct lines. 



The cells of the central tendon, suspensory ligament and dia- 

 phragm, although smaller than those of the omentum and mes- 

 entery, resemble them otherwise quite closely. Classified in the 

 order of their size their order would be: diaphragm, suspen- 

 sory ligament, central tendon, mesentery, omentum, — the lat- 

 ter being the largest. If the straightness of the intercellular 

 lines is taken as a basis the order would be : diaphragm, central 

 tendon, mesentery, suspensory ligament, omentum, — the latter 

 having the most wavy lines. This classification has little sig- 

 nificance, however, for as Schwartz (20) and Muscatello (14) 



Note.— In this paper reference to the literature is made by means of number 

 inclosed in ( ). The titles of the papers or books referred to will be found in 

 the Bibliography, page 245. 



