CH. IV.] 



ADIPOSE TISSUE 



demonstrated by extracting the contents of the fat-cells with 

 ether, when the shrunken, shrivelled membranes remain behind. 

 By mutual pressure, fat-cells assume a polyhedral figure (fig. 67). 

 When stained with osmic acid fat-cells appear black. 



The cells are surrounded by capillary blood-vessels (fig. 68) ; 

 the little clusters thus formed are grouped into small masses, and 

 held so by areolar tissue. 



The oily matter contained in 

 the cells is composed of the 

 compounds of fatty acids with 

 glycerin, which are named olein, 

 stearin, and palmitin. 



Development of Adipose 

 Tissue. Fat-cells are de- 

 veloped from connective-tissue 

 corpuscles ; connective - tissue 

 cells may be found exhibiting 

 every intermediate gradation 

 between an ordinary connective- 

 tissue corpuscle and a mature 

 fat-cell. The process of develop- 

 ment is as follows : a few small 

 drops of oil make their appear- 

 ance in the protoplasm and by 

 their confluence a larger drop 

 is produced (figs. 69 and 70) : 

 this gradually increases in size 

 at the expense of the original 

 protoplasm of the cell, which 

 becomes correspondingly dimi- 

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

 with a flattened nucleus imbedded in its substance (fig. 66). 



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

 found in adipose tissue, which subdivide until each lobule of fat 

 contains a fine meshwork of capillaries ensheathing each individual 

 fat-cell (fig. 68). Although nerve fibres pass through the tissue, 

 no nerves have been demonstrated 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 

 reabsorbed into the blood when occasion requires, and, being 

 used up in the metabolism of the tissues, helps to preserve the 

 heat of the body. 



b. Part of the fat which is situated beneath the skin must, by 

 K.P. E 



a. 



Fig. 69. A lobule of developing adipose tissue 

 from an eight months' foetus, a, Spheri- 

 cal or, from pressure, polyhedral cells 

 with large central nucleus, surrounded 

 by protoplasm staining uniformly with 

 hsematoxylin. b, Similar cells with spaces 

 from which the fat has been removed 

 by oil of cloves, c. Similar cells show- 

 ing how the nucleus with enclosing 

 protoplasm is being pressed towards 

 periphery, d, Nucleus of endothelium 

 of investing capillaries. (McCarthy.) 

 Drawn by Treves. 



