318 INTEGUMENTS. 



is interposed between them in thin laminse. On separating 

 these fibres, the intervening laminae are resolved or drawn out 

 into fine filaments, which, finally, break after being stretched to 

 a certain extent. The lamina which surrounds the whole body 

 of the muscle, and constitutes its sheath, on being put upon the 

 stretch, also tears after having been attenuated into still thinner 

 laminae and into fibres. 



If air be blown into the sheath of a muscle, this sheath is 

 distended into a multitude of cells of various forms and sizes, 

 which have no determined shape, and do not upon expulsion 

 of the air return to the same shape upon a repetition of the in- 

 flation. These cells communicate very freely; all limpid fluids 

 pass with the greatest ease from one to the other, so that from 

 any single point they may, by the force of injection, be distri- 

 buted throughout the body; this is manifested in emphysema, 

 where from a small wound in the thorax, air becomes univer- 

 sally diffused. Fluids of any kind, except they be inspissated, 

 when deposited in these cells, are subject to the common laws 

 of gravity, and continue to descend successively from the high- 

 er to the lower cells, as in anasarca. Blood traverses them 

 very readily in ecchymosis. 



Cellular tissue enjoys a good deal of elasticity, for when 

 stretched it readily returns upon itself. When .very thin, as 

 between the fibrillse of muscles, it is colourless or nearly so, and 

 of a gelatinous or glue-like consistence ; but when its lamina? 

 are thicker, it is of an opaque white, and has a strength 

 amounting almost, to that of ligamentous matter. When dried 

 it becomes crisp and of a dark brown ; but may be restored to 

 its colour and condition by soaking in water. It is only 

 very slightly affected by the usual heat of the culinary pro- 

 cesses of roasting or boiling, as our dishes of meat daily prove; 

 but may be resolved into gelatine after a protracted ebullition. 

 Its putrefaction is slow, and cannot be accomplished, by mace- 

 ration, under several months. 



The cellular substance is pervaded by a large number of 

 blood vessels, the majority of which do not, in a natural state, 

 convey obviously red blood; but if any portion of it be ex- 

 posed for a short time to the air, or to any other unusual sti- 

 mulus, it quickly becomes suffused with red blood, circulating 

 through an infinitude of channels. It cannot, however, be con- 



