GENERAL INTRODUCTION TO VITAMIN THEORY 21 



such time as chemical names can properly be assigned to them, these 

 substances be known by alphabetical designations qualified only by such 

 statement of their solubilities as may seem helpful. In his earlier rations 

 of supposedly purified foodstufifs McCoUum unwittingly furnished 

 water-soluble vitamin in the lactose fed. Hence he at first concluded 

 that the fat-soluble substance of butter, egg-fat, etc., was the only 

 unidentified substance essential to normal nutrition. Thus this became, 

 in his alphabetical terminology, "fat-soluble A," and the water-soluble 

 substance which he next recognized as essential was designated as 

 "water-soluble B." A little later the antiscorbutic substance was in- 

 cluded in the alphabetical terminology as "water-soluble C." 



In 1920, Drummond suggested that the designations then most 

 common, those of Funk and of McCollum, be combined and simplified 

 both for convenience and to free them from questionable implications 

 as follows : That the familiar alphabetical designations be retained but 

 without the antecedent statements of solubility: and that the original 

 designation of Funk be retained in part but the final "e" be dropped, so 

 that the resulting word intamin shall carry no implication as to the 

 chemical constitution of the substance. The three substances then 

 recognized as belonging to this group thus became vitamin A, vitamin 

 B, and vitamin C, respectively, and the way was left open for any 

 others, whose existence might be demonstrated before they are chemi- 

 cally identified, to be added in chronological order and in alphabetical 

 sequence in one series regardless of solubilities. This suggestion has 

 now been so generally adopted that it will here be regarded as estab- 

 lished usage, though the adjective indicating the originally observed 

 solubility or the physiological significance of a vitamin may still be used 

 in any case in which it seems helpful to the discussion in hand. Espe- 

 cially important is it in our judgment to avoid habits of thought or 

 expression which might prejudice the interpretation of future experi- 

 ments ; and, on the other hand, terminology should be recognized for 

 merely what it is and should not be blamed for "misdirected research." 



Since 1920, all qualified students of the subject have recognized the 

 existence of at least the three vitamins. A, B, and C; though perhaps 

 not all have recognized with equal clearness that any one of these terms 

 as originally introduced might, with the growth of knowledge through 

 further investigation, be found to have covered more than one sub- 

 stance. As a matter of fact, the subsequent additions to the vitamin 

 alphabet have arisen not so much by wholly new discovery as by diflfer- 

 entiation. 



Whereas formerly the terms vitamin A and fat-soluble vitamin were 



