44 



THE CONNECTIVE TISSUES 



[CH. IV. 



subcutaneous tissue of the eyelids, penis and scrotum, the nymphoe, 



and the cavity of the cranium. 



Adipose tissue is developed in connection with areolar tissue, and 



forms in its meshes little masses of unequal size and irregular shape, 



to which the term lobules is applied. 



Under the microscope adipose tissue is 

 found to consist essentially of little vesicles 

 or cells which present dark, sharply-defined 

 edges when viewed with transmitted light: 

 they are about -^ or -^^ of an inch in 

 diameter; each consists of a structureless 

 and colourless membrane or bag formed of 

 the remains of the original protoplasm of 

 the cell, filled with fatty matter, which is 

 liquid during life, but is in part solidified 



FIG. 66. Kat-ceiis from the ( O r sometimes crystallised) after death. A 



omentum of n rat. (Klein.) v , , * J / . 



nucleus is always present in some part or 



other of the cell protoplasm, but in the ordinary condition of the cell 

 it is not easily or always visible (fig. 67). 



This membrane and the nucleus can generally be brought into 

 view by staining the tissue : it can be still more satisfactorily demon- 

 strated by extracting the contents of the fat-cells with ether, when 

 the shrunken, shrivelled membranes remain behind. By mutual pres- 



FIG. 67. Group of fat-cells (F c) with capillary vessels (c). (Noble Smith.) 



sure, fat-cells assume a polyhedral figure (fig. 68, &). When stained 

 with osmic acid fat-cells appear black. 



The oily matter contained in the cells is composed of the com- 

 pounds of fatty acids with glycerin, which are named olein, stearin, 

 and palmitin. 



Development of Adipose Tissue. Fat-cells are developed from 



