COXXECTIVE TISS f /:>. 



49 



brushed away, leaving the fibres intact. In many situations the interstices of the 



fibres are filled with rounded granular corpuscles, and the tissue is then termed 



lymphoid or adenoid tissue. The neuroglia, 



or fine gelatinous connective tissue which 



supports the nervous elements in the 



cerebro-spinal axis and in the retina has 



been regarded as a modified form of the 



retiform connective tissue. It is now 



known, however, to consist of cells which 



send off very numerous fine processes, and 



develop from the epiblast, certain of the 



cells forming the wall of the medullary 



canal, becoming neuroglia cells, while the 



remainder become nerve-cells. 



3. Basement-membranes, formerly de- 

 scribed as homogeneous membranes, are 

 really a form of connective tissue. They 

 constitute the supporting membrane, or 

 membrana propria. supporting the epithe- 

 lium of mucous membranes or secreting 

 glands, and in other situations. By means 

 of staining with nitrate of silver they may 



be shown to consist of flattened cells in close apposition, and form therefore an 

 example of an epithelioid arrangement of connective-tissue cells. In some situ- 

 ations the cells, instead of adhering by their edges, give off branching processes, 

 which join with similar processes of other cells, and so form a network rather 

 than a continuous membrane. 



Adipose Tissue. In almost all parts of the body the ordinary areolar tissue 

 contains a variable quantity of adipose or fatty tissue. The principal situations 

 where it is not found are the subcutaneous tissue of the eyelids, the penis and 

 urn. the nymphfe, within the cavity of the cranium, and in the lungs, 

 except near the roots. Nevertheless, its distribution is not uniform, in some parts 

 being collected in great abundance, as in the subcutaneous tissue, especially of the 

 abdomen : around the kidneys ; on the surface of the heart between the furrows ; 

 and in some other situations. Lastly, fat enters largely into the formation of the 



FIG. 18. Retiform connective tissue, from. & 

 lymphatic gland : most of the lymph-corpuscles 

 a're removed. (From Klein's Elements of Histology.) 

 a. The reticulum. c. A capillary blood-vesseL 



FIG. 19. Adipose tissue. High power, a. Starlike appearance, from crystallization of fatty acids. 



marrow of bones. A distinction must, however, be made between fat and 

 adipose tissue ; the latter being a distinct tissue, the former an oily matter, which 



