348 HUMAN PHYSIOLOGY 



In the Orient the victims of beri-beri have usually been 

 people subsisting largely on rice. The disease progresses 

 through two stages. In the first there is steady loss of 

 weight and strength. In the second there sets in a 

 general neuritis, that is, an inflammation and de- 

 generation of the nerve trunks. This is naturally most 

 serious since it leads to sensory and motor paralyses 

 of greater or less extent. Death may result or there 

 may be lasting defects of sensation and motor control. 



Beri-beri appears to be caused by the lack of a vitamin. 

 The compound is one which has apparently been isolated 

 and is not of great complexity. A neuritis like that of 

 beri-beri can be induced in animals by restricting them 

 to certain foods, and then overcome by adding to the 

 diet a minute quantity of the pure vitamin. It is a 

 most interesting fact that the husk or pericarp of rice 

 furnishes the vitamin which is not present in the kernel. 

 What is called "polished rice" has been freed from the 

 pericarp and will cause something like beri-beri in pigeons 

 if they are given nothing else to eat. After the symp- 

 toms are marked the birds can be restored to health 

 by including the husks with the polished grains. 



The so-called vitamin of beri-beri can be derived not 

 only from the husks of rice but from meat, yeast, pota- 

 toes, and other sources. Any diet that is not severely 

 limited in variety will be certain to afford it. It can 

 be said of polished rice, as of gelatin, that it is not un- 

 wholesome but merely insufficient by itself. Either 

 may be most valuable when associated with other foods. 



The course of events when beri-beri is coming on has 

 been analyzed as follows: The vitamin is primarily 

 needed by the nerves. Some of it is present in other 

 tissues as we may infer from the remedial virtue of 

 meat. When none is supplied by the diet the gradual 

 disintegration of the vitamin in the nerves is no longer 

 compensated by the food. The need will be met for 

 a while by abstracting the vitamin from other parts 

 of the body. But to remove any essential constituent, 



