x FOOD AND FOOD-PLANTS 119 



because olive oil is not very easy to digest, and it 

 would be impossible to take all the fat that is 

 necessary for them in that form. 



To sum up then, wherever man lives he must 



Fia. 29. An Olive Grove. 



have in his food proteid, carbohydrates, that is 

 starch and sugar, and fat. The farther north he 

 lives, however, the more fat he must have, while in 

 warm climates very little fat is necessary. It 

 seems also to be true that in the colder climates he 



