THE AEEOLAR TISSUE. 



287 



pearance produced by inserting a quill under the skin of the chest, 

 and blowing forcibly through it a general emphysema being thus 

 promptly produced. The air is, however, removed by absorption 

 within a few hours without any injurious results. This experiment 

 also demonstrates the free communication of the areolse with each 

 other over the whole body even. 



Chemical Composition of Areolar Tissue. 



Areolar tissue abounds in water, since its serous fluid consists 

 mostly of it. Besides, both the white and the yellow fibrous tis- 

 sues contain a considerable percentage of it. Of course, glutin is 

 obtained from areolar tissue by boiling; from the osteine contained 

 in its white fibrous tissue. Elasticine exists in the elastic tissue. 

 In addition to these, we have only to refer to the composition of 

 the transudations for the amount of albumen and saline matters 

 they contain (p. 182). 



Properties of Areolar Tissue. 



Areolar tissue has no characteristic vital properties, since this is 

 the fact with regard to both of its two component elements. Like 

 them it is distinguished by physical properties merely; the princi- 

 pal being extensibility and elasticity, with a good degree of strength. 

 It owes the last property to the collagenous element, and the other 

 two to the elastic tissue. If it be asked how a tissue formed in 

 great part of an entirely inextensible element (the white fibrous 

 tissue), becomes extensible, we have to 

 remember that in extending the areolar 

 tissue the individual fasciculi of white 

 fibrous tissue are not stretched, but are 

 merely displaced upon each other; while 

 the elastic fibres restore them to their 

 original relations after the tension is re- 

 moved. 



The only vital property manifested by 

 this tissue is the one common to all the 

 tissues mentioned thus far ; viz., the power 

 of maintaining its own nutrition. The 

 nutritive changes are, however, probably 

 but slowly brought about, after it is once fully developed, and the 

 vessels in its substance are mostly on their way to other tissues. 



Fig. 183. 



Vessels of areolar tissue from the 

 neck of a young pig. a, a. Nerves. 

 (Queckett.) 



