54 COXXECTIVE TISSUE. 



of the areolar tissue has been named the " penetrating," " constituent,'* 

 or " parenchymal." 



It thus appears that the areolar is one of the most general and most 

 extensively distributed of the tissues. It is, moreover, continuous^ 

 throughout the body, and fi'om one region it may be traced without 

 interruption into any other, however distant ; a fact not without 

 interest in practical medicine, seeing that in this way dropsical waters, 

 air, blood, and urine, effused into the areolar tissues, and even the 

 matter of suppuration, when not confined in an abscess, may spread far 

 from the spot where they were first introduced or deposited. 



On stretching out a portion of areolar tissue by drawing gently asunder 

 the parts between which it lies, it presents an appearance to the naked 

 eye of a multitude of fine, soft, and somewhat elastic threads, quite trans-: 

 parent and colourless, like spun glass ; these are intermixed with fine 

 transparent films, or delicate membranous lamina3, and both threads and 

 laminee cross one another irregularly and in all imaginable directions 

 leaving open interstices or areola between them. These meshes are» 

 of course, more apparent when the tissue is thus stretched out ; it is 

 plain also that they are not closed cells, as the term " cellular tissue " 

 might seem to imply, but merely interspaces, which open freely into one 

 another : many of them are occupied by the fat, which, however, does 

 not lie loose in the areolar spaces, but is enclosed in its own vesicles. 

 A small quantity of colourless transparent fluid is also present in the 

 areolar tissue, but, in health, not more than is sufficient to moisten it. 

 This fluid is generally said to be of the nature of scrum ; but it is not 

 improbable that, unless when unduly increased in quantity or altered 

 in nature by disease, it may resemble more the liquor sanguinis, as is. 

 the case with the fluid of most of the serous membranes. 



On comparing the areolar tissue of different parts, it is observed in 

 some to be more loose and open ni texture, in others more dense and 

 close, according as free movement or firm connection between parts 

 is to be provided for. In some situations, too, the laminae are more 

 numerous ; in others the filamentous structure predominates, or even 

 prevails exclusively ; but it does not seem necessary to designate these 

 varieties by particular names, as is sometimes done. 



Fibres. — When examined under the microscope, the areolar tissue 

 is seen to be principally made up of exceedingly fine, transparent, and 

 apparently homogeneous filaments, from about -j-o^^oth to o^-^ooth of an 

 inch in thickness, or even less (fig. 28). These are seldom single, being 

 mostly united by means of a small and usually imperceptible quantity 

 of a homogeneous connecting substance into bundles and filamentous 

 laminse of various sizes, which to the naked eye, appear as simple 

 tlireads and films. Though the bundles may intersect in every direction, 

 the filaments of the same bundle run nearly parallel to each other, and 

 110 one filament is ever seen to divide into branches or to unite with 

 another. The associated filaments take an alternate bending or waving 

 course as they proceed along the bundle, but still maintain their general 

 parallelism. This wavy aspect, which is very characteristic of these 

 filaments, disappears on stretching the bundle, but returns again when 

 it is relaxed. 



The filaments just described, though transparent when seen with 

 transmitted light under the microscope, appear white when col- 

 lected in considerable quantity and seen with reflected light ; and they 



