OF THE COMMON ADIPOSE TISSUE. ' 137 



plumpness in a few days. Animals that are famished, such as 

 hogs, very soon become fat. Certain birds fatten, it is said, in 

 moist weather, in less than twenty-four hours; emaciation, in 

 many cases is equally rapid. The circumstances most favoura- 

 ble to the secretion of fat, are castration, and the absolute rest 

 of the animal and intellectual organs. These causes are fre- 

 quently united when we wish to fatten animals : they produce 

 a similar effect upon man. Habitual bleedings, sweet and 

 amylaceous aliments, are also regarded as favouring the pro- 

 duction of fat. Besides these, there are unknown circum- 

 stances, which appear to act in the same way, for we remark 

 extraordinary cases of obesity, for which it is difficult to ac- 

 count. The causes which accelerate the absorption of the fat, 

 are in general, the opposite of those above mentioned, in addi- 

 tion to which are, abundant secretions, organic diseases, and 

 particularly those of the organs of the nutritive functions. 



168. Many hypothetical uses have been attributed to the 

 fat. Those which it really possesses, are local and general. 

 In fact, the uses of fat are in part purely mechanical, or of po- 

 sition, such as to lessen pressure, in the sole of the foot, in 

 standing, in the buttocks while sitting, and jointly with the 

 cellular tissue to fill up the hollows, and thereby give a round- 

 ness to the parts; thus we see those of women and children to be 

 the most so, they having most fat. It has been said, that the fat 

 served as a defence frpm cold, because this fluid is a bad con- 

 ductor of heat, and that the animals which inhabit cold coun- 

 tries, have a thick layer of it under their teguments. Admitting 

 this to be so, it is not by the surface of the skin, at any rate, 

 that the fat could preserve warmth. It has been asserted, but 

 without reason, that it lessened the nervous action, and the 

 action of the muscles, i. e. the muscular energy and sensi- 

 bility: in this case, cause has been mistaken for effect. The 

 fat has been thought to supple the fibres. Fourcroy, remem- 

 bering that this fluid contains an excess of hydrogen, thought 

 it destined to render the nutritive substance more nitrated, by 

 depriving it of a part of its hydrogen. Several authors, and 

 even Bichat himself is inclined to the opinion, have thought 

 that the fat might serve to oil the skin by a sort of porous 



