120 TILLEES OF THE GEOUND CHAP. 



requires more proteid than in the warm ones. For 

 both these reasons vegetable food is more important 

 to people in warm climates and animal food to 

 people in cold ones, for they must have much 

 digestible animal fat and much proteid. For 

 instance, the Eskimo in the Far North take 

 practically no vegetable food, while many of the 

 peoples in the tropics take practically * no animal 

 food, and between the two we have all gradations. 



Now let us go back to the kinds of plant food. 

 We find that the seeds which man uses as food 

 contain more proteid and more fat than any other 

 parts of plants. The roots which he uses usually 

 contain a certain amount of proteid, but very little 

 fat ; their chief contents are starch or sugar. 

 Fruits contain chiefly sugar or more rarely starch ; 

 they have very little proteid, and not usually any 

 fat. 



The reason of all this is easily seen. Seeds, as we 

 know, contain the young plant. Just as the cow's 

 milk contains everything that the calf wants, so 

 the seed contains everything that the little plant 

 wants till it is able to feed itself, except one thing. 

 The calf requires at first absolutely nothing but 

 milk, but the little plant cannot begin to grow 

 until it is supplied with water from without, 

 for the seed contains very little water. It is, 

 therefore, a very compact mass of food-stuff. 



