298 GENERAL ZOOLOGY 



question does not properly come within the scope of this 

 book and our attention will be directed to the more strictly 

 zoological aspects of man's activities. 



Self-maintenance. Judging by the structure of the 

 teeth and other parts concerned with nutrition, man is 

 fitted to live on a diet consisting of fruits, herbs, and flesh. 

 Savages often eat much of their food raw and devour 

 things which have little appeal to civilized tastes. The 

 American Indian revels in dog feasts; the primitive 

 Australians esteem the luscious caterpillar as a great 

 delicacy. Each race has certain food customs which are 

 adhered to more or less strictly. The Italian loves his 

 spaghetti; the Irishman relishes potatoes; the Australian 

 prays to his gods that caterpillars may be abundant; the 

 Hawaiian subsists largely on crabs and fish. 



Though a man's body may be maintained for a con- 

 siderable time by eating nothing but protein food, it thrives 

 best on a varied diet including proteins, carbohydrates and 

 fats.* Men forced to live without vegetables often have 

 the scurvy or other similar diseases due to improper nutri- 

 tion. Recently it has been discovered that certain foods 

 contain very small quantities of substances (so-called 

 vitamines, etc.) which play a very important role in nutri- 

 tion, though they furnish very little actual building material 

 or energy. For example, people living largely on polished 

 rice may be attacked by the disease known as beri-beri ; 

 whereas those eating the same proportion of rice which has 

 the outer brown covering are without such trouble. In 

 the fat of butter there are minute quantities of another 

 substance which stimulates growth. To have the greatest 

 value, proteins, carbohydrates, and fats should occur in 

 fairly definite proportions. The daily requirements for 

 an average man as estimated by Atwater are as follows: 



Protein 125 grammes (4.41 oz.) 



Fats 125 grammes (4.41 oz.) 



Carbohydrates 400 grammes (14.11 oz.) 



* For definitions of these substances, see page 30. 



