304: 



THE TISSUES. 



Fig. 190. 



Adipose tissue of sperm-whale. A, 



cranial cavities sometimes yield 20 tons. Hibernating animals lay 



up a large store of fat as the winter sea- 

 son approaches, and which is consumed 

 to maintain the animal heat during their 

 dormant winter state. Hence they are 

 found to be again comparatively ema- 

 ciated on emerging in the spring from 

 their winter quarters. In the camel, the 

 "humps" are masses of adipose tissue, 

 and are absorbed to sustain the animal, 

 if suffering from privation of food. 



In birds, fat is found deposited prin- 

 cipally between the abdominal muscles 

 and the peritoneum. In aquatic birds it 



A. Cells containing crystals of sperma- j g deposited in the bonCS of the leffS. and 

 ceti. B, B. Crystals of spermaceti on , i i \ , -\ n 1-1 i n >i 



the outside of cells. (Queckett.) the last bone f the W1D S S and f the 



tail. 



In reptiles, fat is found chiefly in the abdomen. 



In fishes, fat-cells are distributed throughout the body generally, 

 except in the cod, the haddock, and the whiting. In all these, fat 

 is found only in the liver. (See p. 79.) 



It has been seen that fat-cells do not exist in the invertebrate ani- 

 mals. Fat, however, abounds, in the form of globules, in the mol- 

 lusca (oyster, &c.) ; and in the insect, both in the pupa and in the 

 perfect (or imago) state. 



The trying out the fat of the lower animals consists in heating the 

 adipose tissue till the fat-cells burst and set free their contents. The 

 scraps are the remaining areolar tissue and vessels. 



Uses of Fat as a Tissue. 



Adipose tissue fulfils merely chemico-physical offices in the or- 

 ganism. 



1. It renders the skin soft and flexible. Keference is here made 

 to the fat in the superficial fascia, or subcutaneous areolar tissue. 



2. It gives roundness and symmetry, and hence grace and beauty, 

 to the body. Hence it is more abundant in the female. 



3. It is a protection against pressure ; as on the nates, mons ve- 

 neris, lacteal glands, &c. 



4. It facilitates motion ; as package between muscles, as depo- 

 sited under the skin, around the eyeballs and the heart, and in the 

 omentum. 



5. It is a protection against cold, being a bad conductor of heat. 

 Thus it is found under the skin, around the heart and large vessels, 

 the lacteal glands, in the great omentum, &c. 



