OUR DIET 363 



Fat is stored away in the spaces of connective tissue, as under the 

 skin (cf. Fig. 291, 392), between the muscles, and among the organs 

 of the abdomen. Fat so stored forms fat tissue. Animals that are 

 inactive in winter (hibernate ; cf. 342) usually store up a large amount 

 of fat to nourish their bodies during their long fasting. The blubber 

 of the whale is a thick layer of fat stored under the skin. The camel's 

 hump is fatty material that can be drawn upon when the animal has no 

 opportunity for feeding. 



370. Our Diet. Does it make any difference what kind 

 of coal we burn under a steam boiler? If you were to ask 

 a wide-awake engineer such a question, he would prob- 

 ably answer (cf. 73): "Certainly it does. Some coals 

 give more heat than others. Some coals leave great 

 quantities of clinkers, while others burn up clean. And 

 the most expensive coal is not always the best." So it is 

 with the fuel of the body, our food. It makes a great 

 deal of difference what kind of food we eat, how it is 

 cooked and served, and what it costs. We need to eat 

 some food for the energy it will give us, and some for its 

 power of building the worn-out tissues. Some apparently 

 good food is mostly waste, like the clinkery coal ; and some 

 food, though expensive to buy, has not a high nutritive 

 value. 



The study of diet forms a science by itself; it is called 

 dietetics. Its experts are very careful to plan what they 

 call a "balanced ration," and a housekeeper should be 

 equally particular. A meal should not consist all of one 

 kind of nutrients, or some of the digestive organs, or their 

 ferments, will be overtaxed with work, while others will 

 have nothing to do. The housekeeper has a great 

 responsibility, no* only for the health of the persons fed, 



