

ADIPOSE TISSUE. 



409 



considerable quantity of it, immediately under the skin, and 

 especially under the skin of the abdomen. 



It is also between the muscles, in the orbits of the eyes ; in 

 the omentum and mesentery ; in the joints and the bones ; as 

 well as about the kidneys, and heart also, in elderly persons. 

 In the foetus, and for some time after birth, it appears to be 

 confined to the parts immediately under the skin, but it soon 

 becomes more diffused. The fat in the adipose tissue, is 

 unorganized, and at the common temperature of the human 

 body, is almost fluid. On the latter account it produces that 

 softness and smoothness of the exterior, particularly obvious in 

 obese individuals. Its use, probably, besides contributing to 

 the roundness and softness of the exterior, is in part to protect 

 the body against the extremities of heat and cold, in conse- 

 quence of its being a bad conductor of caloric. It may be 

 considered also, as a deposit of nutriment held in reserve, to be 

 dissolved and taken up again by the absorbents, in a protracted 

 fast, or when any wasting disease has impaired the functions of 

 nutrition. Adipose tissue, belongs to the most simple structures 

 of the body. It differs from cellular tissue even to the knife 

 and eye, by the toughness and coarseness of its web, and con- 

 sists of completely closed membranous cells containing the more 

 or less fluid fatty matter. They are affixed according to Mas- 

 cagni, each one to an artery and vein, the branches of these ves- 

 sels by which the fat is deposited, being distributed around the 

 cell. The fat after being deposited in the cells becomes more 

 consistent by absorption ; it is kept moist by a serous secretion 

 from the walls of the cell, which effectually prevents its transu- 

 dation into the neighboring tissues. If the fat be reabsorbed, 

 the cells which have no communication with each other, col- 

 lapse and vanish. The diameter of these vesicles or cells, in 

 man, vary from T g to ^ of a line ; in some places as in the 

 spinal marrow, they are still smaller from the ^ to ^ part 

 of a line. In our larger domestic animals, they are of much 

 coarser structure. 



It is observed by dissectors that there are no subjects, how- 

 35 



