ADIPOSE TISSUE . 303 



2. A sedentary or a sluggish life also favors the deposit of fat. 

 Even carnivorous animals, though always lean in 'their natural 

 state, become fat when closely caged, and fed on a mixed diet. 



3. Breathing an atmosphere imperfectly supplied with oxygen, 

 is a third cause of fatty deposit. To this we may also, doubtless, 

 add privation of solar light, and a damp atmosphere. 



4. On the contrary, a diet more exclusively nitrogenized (albu- 

 men, musculine, &c.> as in eggs and lean meat), abstinence from 

 distilled and fermented liquors, and habitual active exercise in the 

 open air, tend to prevent an accumulation of fat, or to remove it if 

 already existing. 



Moreover, emaciation may be induced by a prolonged discharge 

 of any fluid containing a considerable proportion of fat. Hence 

 profuse suppuration or hemorrhage, or excessive sexual indulgence, 

 produces leanness, since pus, blood, and semen are rich in fat (p. 74). 



While the fat in the fat-cells is the most rapidly formed, it is also 

 the most rapidly resorbed-, of all the immediate principles of the 

 human body. It is its sudden diminution around the eyeball which 

 gives the sunken appearance to the eye, even a few hours after the 

 invasion of certain acute diseases. This change is most rapid in 

 children ; and they also most rapidly refill the fat-cells when con- 

 valescence is established. 



Distribution of Adipose Tissue in the Lower Animals. 



Carnivorous animals are naturally lean, since they are necessarily 

 active, and live principally on the nitrogenized immediate princi- 

 ples -contained in the flesh of other animals. 



Herbivorous animals, on the other hand, manifest a tendency to 

 accumulate fat. They are less active, and consume large propor- 

 tions of starch and gum. By way of exception, however, the rabbit 

 is said to be almost entirely destitute of fat, and in some instances 

 none at all can be discovered. There is a species of sheep in Asia 

 which accumulates a mass of fat which is situated in the place of a 

 tail ; which swings to and fro as the animal walks, and sometimes 

 weighs even 40 pounds. Fat is, however, usually most abundant, in 

 ruminating animals, about the kidneys. In others it abounds in the 

 mesentery and the omentum; and in others still, in the areolar tissue 

 under the skin. The latter, in the seal and the whale, is called "blub- 

 ber ;" and from a single whale 120 tons are sometimes obtained 

 the deposit being from 4 to 20 inches thick. Spermaceti is, however, 

 found in the sperm-whale, in two cavities of the cranium; while the 

 cells of the adipose tissue also contain crystals of it. (Fig. 190.) The 



