B VITAMIN DEFICIENCY STATES 421 



Salmon and trout both develop anemias that are cured or prevented 

 by xanthopterin 158 and by folic acid; and xanthopterin apparently 159 

 has at least some activity in the monkey and possibly the goat's milk 

 anemia of rats, but not in the chick. 100 The incubation of xanthopterin 

 with rat liver gives results that indicate, though not unequivocally, that 

 this substance is converted to folic acid or enhances the liberation of 

 folic acid from bound forms. Studies with regard to Bi 2 deficiency in 

 lower animals are as yet fragmentary, although the apparent identity 

 of this vitamin with the "animal protein factor" 161 and the "cow manure 

 factor" 162 provides some evidence of the necessity of this factor in the 

 diets of rats and chicks and of the symptoms resulting from some degree 

 of nutritional deprivation. Anemia has been produced in a pig, however, 

 by using vitamin-free casein and 2 per cent sulfasuxidine in the diet, 

 and a remission obtained by the use of purified liver extract; thus vitamin 

 B X 2 deficiency may be attainable in a number of species when the con- 

 ditions are properly selected. Prior to the isolation of vitamin Bi 2 , how- 

 ever, a satisfactory biological response to the antipernicious anemia 

 factor in animals other than man had been long and ardently sought for 

 in vain as an assay device. The relationship which may exist between 

 vitamin B 12 and cobalt metabolism should now be reviewed in the light 

 of the cobalt content of vitamin Bi 2 and the known lowering of vitamin 

 B 6 blood levels in cobalt-deficient animals. 



Mention should be made of the apparent stimulatory effect of a- and 

 /?-pyracins upon the pteroyltriglutamate activity on hemoglobin forma- 

 tion and growth in anemic chicks. Either of the pyracins alone is ineffec- 

 tive. However, either pyracin with the triglutamate stimulates its effective- 

 ness (/?-pyracin being somewhat more active) in improving growth and 



O — CH 2 



U 



-CH 



a-pyracin fi-pyracin 



preventing anemia. /?-pyracin does not further augment the activity of 

 the monoglutamate in the anemic chick. All three forms of folic acid are 

 apparently active to some degree for both chicks and monkeys, and the 

 pyracins seem to influence favorably the conversion of the triglutamate 

 to the monoglutamate in the chick. Whether this implies an involvement 

 of pyridoxine metabolism in pteroylmonoglutamate formation from its 

 higher conjugates remains unknown. Indeed, recent reports have chal- 



