74 



LOCOMOTION. 



[CHAP. in. 



more the marks of a longitudinal creasing, than a true separation 

 into threads; for it is impossible by any art to tear up the band 

 into filaments of a determinate size, although it manifests a decided 

 tendency to tear lengthwise. The larger of these bands are often 

 as wide as ^-J-^. of an inch ; they branch, or unite with others, here 



Fig. 6. Fig.*J. 



The two elements of Areolar tissue, in their natural rela- 

 tions to one another : a. The white fibrous element, with cell- 

 nuclei, i, sparingly visible on it. 6. The yellow fibrous ele- 

 ment, shewing the branching or anastomosing character of its 

 fibrillae. c. Fibrillae of the yellow element, far finer than the 

 rest, but having a similar curly character, d. Nucleolated 

 cell -nuclei, often seen apparently loose. From the areolar 

 tissue under the pectoral muscle, magnified 320 diameters. 



Development of the Areolar tissue 

 (white fibrous element) : e. Nucleated 

 cells, of a rounded form. /. g. h. The 

 same, elongated in different degrees, and 

 branching. At h, the elongated extre- 

 mities have joined others, and are al- 

 ready assuming a distinctly fibrous 

 character. After Schwann. 



and there. The smaller ones are often too minute to be visible, 

 except with a good instrument. These are the white fibrous element. 



The others are long, single, elastic, branched filaments, with a 

 dark, decided border, and disposed to curl when not put on the 

 stretch. These interlace with the others, but appear to have no 

 continuity of substance with them. They are for the most part 

 about the -Q&Q-Q of an inch in thickness ; but we often see, in the 

 same specimen, others, of much greater density. These form the 

 yellow fibrous element (fig. 6). 



These two tissues may be most easily discriminated by the addi- 

 tion of a drop of dilute acetic acid, which at once swells up the 

 former, and renders it transparent, while it produces no change in 



