TEXT-BOOK OF PHYSIOLOGY. 



pact masses the muscular tissue of the body, etc. Examined with 

 the naked eye, it presents the appearance of being composed of 

 bundles of fine fibers interlacing in every direction. In the embryonic 

 state the elements of this form of connective tissue are united by a 

 ground substance, gelatinous in character. In the adult state this 

 substance shrinks and largely disappears, leaving intercommunicating 

 spaces of varying size and shape, from which the tissue takes its 

 name. When subjected to the action of various reagents, and 

 examined microscopically, the bundles can be shown to consist of 

 extremely delicate, colorless, transparent, wavy fibers, w r hich are 

 cemented together by a ground substance composed largely of mucin. 

 Other fibers are also observed, which are distinguished by a straight 

 course, a sharp, well-defined outline, a tendency to branch and unite 

 with adjoining fibers, and to curl up at their extremities when torn. 

 From their color and elasticity they are known as yellow elastic fibers. 



Distributed throughout the 

 meshes of the areolar tissue 

 are found flattened, irregularly 

 branched, or stellate corpuscles, 

 connective -tissue corpuscles, 

 plasma cells, and granule cells. 



In 



super- 

 posed 

 layers. 



FIG. 7. ADIPOSE TISSUE. 



FIG. 8. FAT-CELLS FROM THE AXILLA 

 OF MAN. i. The equator of the 

 cell in focus. 2. The objective 

 somewhat elevated. 3, 4. Forms 

 changed by pressure, p. Traces 

 of protoplasm in the vicinity of 

 the flat nucleus k. 



Adipose Tissue. This tissue, which exists very generally 

 throughout the body, though found most abundantly beneath the 

 skin, around the kidneys, and in_the bones, is practically but a 

 modification of areolar tissue. In these situations it presents itself 

 in small masses or lobules of varying size and shape, surrounded 

 and penetrated by the fibers of connective tissue. (See Fig. 7.) 

 Microscopic examination shows that these masses consist of small 

 vesicles or cells, round, elliptical, or polyhedral in shape, depending 

 somewhat on pressure. (See Fig. 8.) Each vesicle consists of a thin, 



