VITAMINS 327 



Lunin showed that mice remained healthy on milk alone but died 

 when fed a mixtine of casein, lactose, milk fat, and milk ash in the 

 same proportions as in milk itself. On the basis of these observations 

 he wrote, ". . . other substances indispensable for nutrition must be 

 jjresent in milk besides casein, lactose, fat, and salts." This conclu- 

 sion was the culmination of a series of feeding experiments in which 

 animals failed on diets of purified proteins, carbohydrates, and fats. 

 Again the new idea did not gain general acceptance. 



Actually the disease called scurvy had been recognized in armies and 

 on shipboard since antiquity. At least as early as 1601 oranges and 

 lemons were officially recognized as preventives of the symptoms. Lind 

 published a treatise on scurvy in 1753 in which the cure of severe cases 

 within 6 days was described, using fresh fruits and vegetables. He 

 based his opinion on convincing experiments conducted by himself 

 on sailors. 



In spite of many similar statements, it was apparently not until 

 Dumas and Lunin that unknown factors were suspected as essential to 

 complete nutrition. Even the first systematic prevention and cure 

 of beriberi were mistakenly attributed in 1882 to an increase in dietary 

 protein. This disease, mentioned first in China in 2600 B.C., was 

 eliminated from the Japanese navy by Takaki, Director-General of the 

 Navy Medical Service, who supplemented the diet of polished rice 

 with increased allowances of vegetables and meat and substituted 

 barley for part of the rice. Although Takaki did not realize the 

 idtimate cause of beriberi, he understood correctly that the disease 

 was caused by an imbalanced diet. 



Still another disease, rickets, was attributed to faulty diets, and in 

 1838 Guerin produced it experimentally in puppies to prove the con- 

 nection. 



The prevailing explanation of these cures is well represented by 

 observations made at the end of the nineteenth century on experimen- 

 tal beriberi in chickens. Hens fed rice without bran developed symp- 

 toms that were cured when the bran was added. Eijkman continued 

 (his work, observing that the antiberiberi factor could be readily ex- 

 tracted and that it was small enough to bo dialyzable. However, he 

 regarded the factor as an antidote for an organism he thought oc- 

 curred in rice and caused the disease. 



Again the idea of a special nutritional factor was proposed, this time 

 in 1901 by Grijns, who suggested that beriberi appeared because the 

 diet "lacked certain substances of importance in the metabolism of the 

 central nervous system." Finally, after isolation of the factor in 1912 

 by Funk, nutritionists at last adopted fh^ view ^hat special substances 



