THE VITAMINS 



CHAPTER I 



GENERAL INTRODUCTION TO THE VITAMIN THEORY 



Until recent years the discussion of food values and of nutrition 

 and other life processes from the chemical point of view was hampered 

 by the embarrassing fact that all attempts at prolonged feeding upon 

 artificial mixtures containing the substances known to be necessary in 

 nutrition had ended in failure. Nor were such feeding experiments 

 any more successful when great care was devoted to the chemical purity 

 of the substances fed. Whether nutritive failure resulted from the 

 need of other substances than those known as essential, or from faulty 

 selection or quantitative combination of the nutrients entering into the 

 artificial food mixture remained obscure until the work of Hopkins in 

 England, and of Osborne and Mendel and McCollum and Davis in this 

 country, made it clear that a natural food supply furnishes, and normal 

 nutrition requires, other substances in addition to proteins, fats, carbo- 

 hydrates, water, and salts. With this fact now convincingly established, 

 it is easier to see that it was foreshadowed by many earlier observa- 

 tions than it is to say definitely when or by whom the existence of the 

 substances now known as vitamins was discovered. Our present 

 "vitamin theory" or point of view in regard to this branch of chem- 

 istry is rather the product of development than of any isolated discovery, 

 and much of this development antedates the introduction of the word 

 vitamin. 



Early Evidence from Observations upon Disease 



As early as 1720, Kramer wrote in his Medicina Castrensis that 

 neither medicine nor surgery could give relief in scurvy, "But if you 

 can get green vegetables; if you can prepare a sufficient quantity of 

 fresh antiscorbutic juices, if you have oranges, lemons, citrons, or 

 their pulp and juice preserved with whey in cask, so that you can make 

 a lemonade, or rather give to the quantity of 3 or 4 ounces of their 

 juice in whey, you will, without other assistance, cure this dreadful 

 evil." And Lind confirmed this doctrine by well-controlled experiments 

 upon human subjects. As surgeon of the Salisbury he had, during one 

 voyage, twelve scurvy patients, without sufficient supplies of oranges 



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