TISSUES OF THE BODY. 217 



and paths for vessels and nerves, or they may constitute formed struc- 

 tures, membranes, cords, or solid envelopes. Accordingly, we distinguish 

 two kinds of this tissue, the formed and the formless, a division which 

 is, generally speaking, well based, although it must not be forgotten 

 that there are in many places transitions from the formed to the form- 

 less, and vice versa, and that, therefore, nature has drawn no sharp 

 bounding line between the two species. As a rule (which is not with- 

 out exceptions, however), the first of these is a soft slimy matter, the 

 latter a more solid substance. 



Formless connective-tissue, or, as it has been named when occurring 

 in large quantities, loose or areolar tissue, possesses besides a homo- 

 geneous, gelatinous, and almost mucoid ground-substance, connective- 



Fig. 211. Formless or areolar connective-tissue from the large omentum of man. 

 a, a, a capillary vessel. 



tissue fasciculi, elastic fibres and cells, but in. very varying propor- 

 tions. The interlacing of these fasciculi (in general rather loose, so 

 that the whole remains on that account yielding and extensible) is 

 either retiform, or several of the bundles lie longitudinally together, 

 embedded in and held together by the soft formless substance. By 

 the heaping up of fat-cells within this loose tissue it is opened up, 

 and a number of communicating spaces are produced with septa between 

 them. These are the cells of older anatomists, which procured for 

 the tissue the, designation cellular, a name which has given way to the 

 histological nomenclature of the present clay. We may also succeed 

 mechanically, as for instance by inflation with air, in producing a 

 more or less artificial separation of this substance, which is saturated 

 during life with small quantities of a watery transudation similar to 

 synovia, 96. These " cells " or loculi appear also pathologically on 

 the accumulation of large quantities of fluid or the entrance of air. 



