CELLULAR SUBSTANCE. , 91 



racter as that from the muriatic solution. All these reactions 

 are the same as those of the fibrous coat of the arteries. 



CHAPTER XII. 



OF CELLULAR SUBSTANCE. 



THE name cellular substance or tissue is given to a tissue 

 spread through the whole body, enveloping all the organs, and 

 filling up all the interstices, so as to leave no vacuities in the 

 body. It is made up of pale elastic and extremely fine filaments, 

 interwoven in different ways, so as to form areolse or spaces of 

 various size and figure, and calculated to contain such fluids as 

 may be deposited within them. 



The quantity found in different parts varies considerably. In 

 some parts we trace it in the form of a thin layer lying beneath 

 the skin, and dipping into the interstices between the muscles. 

 It is accumulated in considerable quantity in the flexures of the 

 joints, filling up the popliteal space, the axillaB, and surrounding 

 the vessels at the groin. In the cavity of the abdomen a large 

 deposite is found, usually about the kidneys ; and in the pelvis 

 a loose spongy web fills up the spaces between the reflection of 

 the serous membrane and the different viscera. It may be said 

 that the cellular tissue of each region is continuous with that de- 

 posited in the neighbouring parts, and therefore forms a continu- 

 ous whole throughout the system. 



The general opinion of anatomists at present is that the cel- 

 lular tissue is made up of cylindrical filaments, crossing in va- 

 rious ways, so as to form a net-work. These filaments in most 

 places are aggregated together so as to constitute lamellae, en- 

 closing spaces or cells, which present an infinite variety of forms 

 and of size ; but which still freely communicate, as is evident 

 from what happens in anasarca, and by the diffusion of air over 

 the body, in some cases of empyema. 



The cellular tissue may be divided into two species. The first 

 species is more dense, and shows distinct cells. It is found in 

 the organs furnished with mucous membranes, the adhering face 

 of which it covers. The blood-vessels and nerves are also enve- 

 loped in it. The second species is softer, and contains cells 



