DISCOVERY 



85 



—if not always — caused by a deficiency of that " some- 

 thing " which is now known as accessory food factors, or 

 vitamines. 



In 1881 Lunin stated that, in addition to the dietary 

 units recognised at that time, other substances existed 

 which were equallj^ indispensable for life. 



In 1906 F. G. Hopkins, Professor of Biochemistry 

 in the University of Cambridge, wrote: " No animal 

 can live upon a mixture of pure protein, fat, and carbo- 

 hydrate, and even when the necessary inorganic material 

 is carefully supplied, the animal still cannot flourish. 

 The animal body is adjusted to live either upon plant 

 tissue or other animals, and these contain countless 

 substances other than the proteins, carbohydrates, 

 and fats. 



It was, however, not until early in 1914 that Casimir 

 Fimk issued a detailed and authoritative account of 

 some newly discovered bodies, which he named 

 vitamines, on the erroneous supposition that they were 

 chemically related to ammonia, as indicated by the 

 suffix "-amines." These bodies were stated to be 

 necessary for the growth and preservation of life. 



It is at present generally accepted that there are 

 three distinct vitamines, or accessory food factors, as 

 they are more correctly named. They are : 



1. The Fat-soluble A or Antirachitic Factor. 



2. The Water-soluble B or Antineuritic (Anti- 



beri-beri) Factor. 



3. The Antiscorbutic Factor. 



Their chemical constitution is at present unknown ; 

 but Funk, by chemical processes, obtained a crystalline 

 substance melting at 233' C. , for which he obtained the 

 formula Ci7H„o07N2, while Hofmeister claims to have 

 separated a vitamine of the formula CsHuNOo. 

 J. C. Drummond, however, suggests that, owing to the 

 facility with which vitamines are " adsorbed," they 

 may have been carried down by other precipitates in 

 the process of their isolation and examined and esti- 

 mated as such. 



Notwithstanding the present ignorance respecting 

 their chemical nature, a vast amount of work of an 

 empirical, but none the less conclusive, character has 

 been carried out. These experiments, performed on 

 young and growing animals, were generally of a pre- 

 ventive or of a promotive character, followed by cura- 

 tive measures. In both cases the animals were fed 

 with food well balanced in respect of proteins, etc., 

 but from which vitamines were absent. In the one case 

 preparations containing vitamines were supplied with 

 the food, while in the other case the food was not so 

 supplemented until a cure was thought necessary. The 

 result of these experiments was that, in the absence of 

 vitamines, the animals under experiment suffered from 

 "deficiency diseases " and ultimately died, unless the 



vitamine preparation was administered in time, when a 

 speedy cure was usually effected. The application of 

 these results to human beings is based on the assumption 

 that the causes of failure of nutrition of one kind of 

 mammal would produce untoward results of some kind 

 in other mammals, and most probably the results 

 would differ only in degree. In this way, many foods 

 were approximately standardised in respect of their 

 vitamine or accessory factor content. 



The following table indicates the values obtained in 

 respect of a few substances : 



A represents the Fat-soluble A or Antirachitic Factor. 



B represents the Water-soluble B or Antineuritic (Anti-beri- 

 beri) Factor. 



C represents the Antiscorbutic Factor. 



-|-, -f-f , -f 4- -|- indicate the relative presence of the factor 

 in three degrees. 



o indicates their absence. 



? indicates doubt as to their presence. 



V.S. indicates a very slight quantity, less than 4-- 



WTiere no indication is given in the various columns, no 

 estimation was made. 



Note. — The information in this table is extracted by per- 

 mission of the Medical Research Committee from a more 

 extensive list in the Report mentioned at the end of this article. 



