242 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



RESULTS. 



The great difficulty in the preparation of all mj material was 

 the danger of mechanical injury during the removal of the 

 specimens from the animals, during the staining, and even in 

 mounting. As large pieces as possible were used, some measur- 

 ing 20x30 mm. The difficulty in obtaining large specimens 

 was the presence of blood-vessels and fat; these prevented the 

 use of high powers by not allowing the cover-glass to lie close 

 to the specimen throughout its entire extent. By the exercise 

 of great care specimens of the above mentioned size could be 

 obtained which showed no discontinuities, each epithelial cell 

 being bounded by sharp, continuous lines. 



The distribution of such openings or discontinuities as I was 

 able to demonstrate in the epithelium of the peritoneal cavity 

 of the cat was extremely irregular. Their size and shape was 

 substantially alike on the central tendon of the diaphragm, the 

 mesentery, omentum, suspensory ligament and the peritoneal 

 surface of the diaphragm. 



]^o specimens were obtained where the occurrence of these 

 discontinuities obeyed any general rule or law. For, while 

 specimen "A" from the suspensory ligament might have less 

 than specimen "A" from the mesentery, specimen "B" from the 

 former might have more than "B" from the latter. Their dis- 

 tribution was found to be an entirely arbitrary one with respect 

 to the different regions of the peritoneal cavity. When present 

 the greater majority of these figures were found at the junction 

 of inter-cellular lines, PI. 14, fig. 4. If, however, discontinui- 

 ties were present in very large numbers, they were also found in 

 individual lines as well as at their intersection. 



All manner of variations as to size and shape were found. 

 While in some parts of a given specimen they were more or less 

 circular in shape and located at the junction of several intercel- 

 lular lines, in other parts of the same specimen they would be 

 arranged in chains of various sizes, but usually larger struc- 

 tures, which in some instances nearly equaled the adjacent cells 

 in size, PI. 14, fig. 6. In some specimens one or more nearly 



