PHYSIOLOGY AND THE FOOD PROBLEM 11 



introduction let me first say a few words on vita- 

 mines, a subject on whicli our knowledge is quite 

 recent. 



If an animal is fed on purified proteins, carbo- 

 hydrates, and fats, witli the addition of the neces- 

 sary salts and water, it soon becomes ill and finally 

 dies, even although the amounts administered are 

 physiologically correct. If the animal is a young 

 one, it ceases to grow under the same conditions. 

 A very small addition of a natural food, such as 

 milk, corrects the evil. Foods as they occur in 

 nature contain something extra, and these extra 

 materials, a small quantity of which is essential 

 for normal maintenance and growth, have been 

 dubbed vitamines, or accessory food factors. 



One of them is soluble in water, and is contained 

 in special abundance in the '' germ " present in 

 the outer portions of food grains. In certain parts 

 of the world, for example in Japan, polished rice 

 was used as the main article of diet, and the 

 Japanese suffered in consequence from a disease 

 called beri-beri (dropsy, neuritis, paralysis), not 

 because the rice was poisonous but because it 

 lacked the vitamine. If the outer portion of the 

 rice grain is added to the diet the disease is pre- 

 vented or cured. The Japanese are a practical 

 people, and now that the cause of beri-beri is 

 known, the disease is rapidly becoming a thing of 

 the past. There are also other vitamines ; diseases 



