VITAMINS 613 



Spies and co-workers (2600,2601), Watson (2991), Darby and 

 co-workers (531), and Moore and co-workers (1981); cf. the review 

 of Berry and Spies (21^8). The antipernicious anemia factor of the 

 liver is not able to cure macrocytic nutritional anemia. Scott, Norris, 

 and Heuser (252Jf) found that foHc acid increases the speed of recov- 

 ery from hemorrhagic anemia of the chick, but according to Spies 

 microcytic anemia is not benefited by folic acid. 



Liver extracts contain folic acid, but not in sufficient quantity to 

 explain the action of the antipernicious anemia factor of liver. Com- 

 paratively large amounts (10-20 mg. daily) of folic acid are required 

 to cure pernicious anemia. Macrocytic nutritional anemia is not due 

 to lack of intrinsic factor (Spies and Payne, 2603), nor can folic acid 

 be identical with the extrinsic factor, since it is active in the absence 

 of normal gastric juice and when given parenterally. Spjes suggested 

 that the antipernicious anemia factor may liberate folic acid from a 

 conjugate present in food and yeast. This is supported by recent 

 experiments of Welch and co-workers (3027).* Normal individuals, 

 but not patients with pernicious anemia, convert the conjugate 

 pteroylpolyglutamate of yeast to folic acid, which is excreted in the 

 urine. Liver extract given to pernicious anemia patients increased 

 their folic acid excretion, while normal gastric juice did not convert 

 the conjugate to folic acid. Fresh rat liver is able to sj^nthesize folic 

 acid from pterins (Wright and Welch, 3128). 



Nevertheless, the exact relationship between the actions of the 

 liver factor and folic acid in pernicious anemia require further study. 

 It is of interest that cure can also be effected by treatment with very 

 large doses of thymine (2602), which suggests that the factors are 

 required for nucleic acid synthesis. According to Davis (5If.2) acetyl- 

 choline produces a macrocytic anemia and folic acid increases the 

 acetylcholine esterase in the plasma. 



3.3.2. Vitamins. It can now be considered reasonably established 

 that the following vitamins are required for cytopoiesis or hemo- 

 poiesis : riboflavin (I^28,J^88,5]^7,610,1013,1072,1563,1571,19J^8,2175, 

 2599,2803,2904) ; pyridoxine (319,411,428,^35,610,924,1364,1571,1819, 

 1821,2579,3105); nicotinic acid (428,547 ,610,1013,1124,2235a); pan- 

 tothenic acid (2745,2803); folic acid (cf. above); pterins (1820,2562, 

 2819,2831,3128); vitamin D (53,545,959,1432,1547; cf., however, 

 1806); ascorbic acid (428,643,722,911,1387,1814,1919,1920,1924,2331, 



* Cf. Heinle and Welch {1228a) and Bethell and co-workers {25!ta). 



