VITAMINS 273 



To summarize our knowledge of the chemical nature of the active 

 principle prior to the introduction of the vitamin theory (till 1911) 

 the following may be set down with certainty: 



1. The substance is soluble in water, alcohol, and acidified 

 alcohol. 



2. The substance is dialysable. 



3. The substance is destroyed at 130 c. 



When we took up the question in 1911 it was not known whether 

 the active substance was organic or inorganic, in nature, whether or 

 not it was a constituent of proteins, nucleins, or phosphatides. It 

 was not certain that we were not dealing with a ferment, nor was it 

 known if the substance belonged to some chemical group already 

 described, or to some new unknown class of substances. 



Casimir Funk began his researches in this field 

 shortly prior to 191 1. He set himself the task of isolat- 

 ing the anti-beri-beri substance from its sources and the 

 establishment of its chemical identity. In combina- 

 tion with Cooper, Funk had shown that when pressed 

 yeast was boiled with 20 per cent, sulfuric acid for 

 'twenty-four hours and the sulfuric acid completely 

 removed with baryta, the evaporated filtrate still ex- 

 hibited marked anti-beri-beri qualities. This stability 

 in the presence of an acid led him to believe that the 

 substance must be an organic base. With this assump- 

 tion he began a systematic investigation of large 

 amounts of rice polishings, the results of which he pub- 

 lished in 1911. In testing his fractions he made use of 

 pigeons which had been shown, like chickens, to be 

 particularly susceptible to this disease when fed on pol- 

 ished rice. By careful fractioning Funk was able to 

 isolate from 100 pounds of rice polishings less than 

 2-iooths of an ounce of needle-shaped crystals which 

 melted sharply at 233 F. and were highly curative. 



