282 THE CHEMISTRY OF GROWTH AND REPAIR 



are scanty or absent in lard, olive oil, and most vegetable oils. Funk 

 believed the water-soluble antineuritic agents to be pyrimidine deriva- 

 tives. They are dialyzable (Drummond) and are adsorbed by 

 Fuller's earth (Seidell). Williams and Seidell" have found that 

 hydroxypurines have marked anti-neuritic effects, and they sug- 

 gested that an isomer of adenine- is responsible for the anti-neuritic 

 action of yeast extracts. Later Williams^^ found an active hydroxy- 

 pyridene, and suggested that the curative properties of yeast and 

 rice polishings may be due to an isomeric form of nicotinic acid. These 

 observations await confirmation, and we still are in the dark con- 

 cerning the character of antineuritic vitamines.^^ 



The nature of the ' ' fat-soluble A " is, if possible, even less known than 

 that of "water soluble B." Drummond's investigations^" show that 

 it is somewhat heat resistant, but it is destroyed at 100° for one hour, 

 apparently not through oxidation or hydrolysis. It cannot be ex- 

 tracted from oils by water or dilute acid, but is extracted to some ex- 

 tent by cold alcohol. If the fats are hydrolyzed at room temperature 

 the active factor disappears, and it cannot be identified with any of 

 the recognized components of fats. Because of its thermolability and 

 other properties, Drummond is driven to the conclusion that ''fat- 

 soluble A" is not a clearly defined chemical substance, but rather it is a 

 labile substance, perhaps possessing characteristics resembling those 

 of an enzyme. ^"^^ 



Vitamines, especially those that are water-soluble, also favor 

 the growth of bacteria, ^"^ and are essential for the growth of yeast, 

 so that Williams^^" has found it possible to determine the amount of 

 this vitamine present in a food stuff by the rate of growth of yeasts 

 thereon. Typhoid bacilli are said to produce vitamines during 

 their growth, ^'^'^ and if it is true, as has been stated, that neither 

 plants nor animals seem able to synthesize them, it would seem that 

 they must be of bacterial origin. Yeast is known to produce water- 

 soluble vitamine in particular abundance, but not the fat- soluble 

 vitamine. Other sources of water-soluble vitamines are numerous, 

 especially green vegetables and whole cereals, but they are not so 

 abundant in meat or milk.^°« 



Why the vitamines are essential and how they act is unknown. 

 It^s suggestive that they are found especially in cells with an active 

 metabolism, but whether as a result of this activity or because essential 



" Jour. Biol. Chem., 1916 (26), 431. 

 '« Jour. Biol. Chem., 1917 (29), 495. 



'^ See review by Drummond, Biochem. Jour., 1917 (11), 255. 

 "» liiochem. Jour., 1919 (13), 81. 



■"•"See also Steenbock and Boutwell, Jour. Biol. Chem., 1920 (41), 163. 

 "''See D. J. Davis, Jour. Infect. Dis., 1917(21), 392; Kligler, Jour. Exp. Med., 

 1919 (30), 31. 



^'"^ Jour. Biol. Chem., 1919 (38) 465; also Baehmann, ibid., (39), 235. 



■""' Pacini and llussell, Jour. Biol. Chem., 191S (34), 43. 



"""See Osborne and Mendel, Jour. Biol. Chem., 1919 (39), 29; 1920 (41), 515. 



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