STRUCTURE OF THE ELEMENTARY TISSUES. 



37 



appearance in the protoplasm: by their confluence a larger drop is pro- 

 duced (Fig. 37): this gradually increases in size at the expense of the orig- 

 inal protoplasm of the cell, which becomes correspondingly diminished 

 in quantity till in the mature cell it only forms a thin crescentic film, 

 closely pressed against the cell-wall, and with a nucleus imbedded in its 

 substance (Figs. 34 and 37). 



Under certain circumstances this process may be reversed and fat -cells 

 may be changed back into connective-tissue corpuscles. (Kolliker, Yir- 



<3llOW. 



FIG. 36. FIG. 37. 



FIG. 36. Blood-vessels of adipose tissue. A. Minute flattened fat-lobule, in which the vessels only 

 represented, a, the terminal artery; v, the primitive vein; 6, the fat vesicles of one border of 

 le lobule separately represented. X 100. B. Plan of the arrangement of the capillaries (c) on the 

 cterior of the vesicles: more highly magnified. (Todd and Bowman.) 



FIG. 37. A lobule of developing adipose tissue from an eight months' 1 foetus, a. Spherical, or, 

 from pressure, polyhedral cells with large central nucleus, surrounded by a finely reticulated sub- 

 stance staining uniformly with haematpxylin. b. Similar cells with spaces from which the fat has 

 been removed by oil of cloves, c. Similar cells showing how the nucleus with enclosing protoplasm 

 is being pressed towards periphery, d. Nucleus of endothelium of investing capillaries. (McCarthy.) 

 Drawn by Treves. 



Vessels and Nerves. A large number of blood-vessels are found in 

 adipose tissue, which subdivide until each lobule of fat contains a fine 

 mesh work of capillaries ensheathing each individual fat-globule. Al- 

 though nerve fibres pass through the tissue, no nerves have been demon- 

 strated to terminate in it. 



The Uses of Adipose Tissue. Among the uses of adipose tissue, 

 these are the chief: 



a. It serves as a store of combustible matter which may be re-ab- 

 sorbed into the blood when occasion requires, and, being burnt, may 

 help to preserve the heat of the body. 



I. That part of the fat which is situate beneath the skin must, by its 

 want of conducting power, assist in preventing undue waste of the heat 

 -of the body by escape from the surface. 



