PYRIDOXINE 



a diet not containing pyridoxine.^ The difference in the behaviour of 

 the two groups of beetles was shown to be due to the presence in this 

 second group of intracellular symbiotic micro-organisms, capable of 

 supplying, inter alia, pyridoxine ; ^-® for sterilised larvae failed to grow 

 on a purified diet, whereas the unsterilised larvae developed normally. 

 Pyridoxine was essential for the growth of the larvae of the rice 

 moth, Corcyra cephalonica.^ On a vitamin Bg-deficient diet containing 

 tryptophan, these larvae excreted a yellow compound similar to, but 

 apparently not identical with, xanthurenic acid,^ an observation re- 

 calling the excretion of xanthurenic acid by vitamin Bg-deficient dogs. 



References to Section i8 



1. E. L. Tatum, Proc. Nat. Acad. Sci., 1939, 25, 490 ; 1941. 27, i93- 



2. W. Trager and Y. SubbaRow, Biol. Bull. Woods Hole, 1938, 75, 75. 



3. Y. SubbaRow and W. Trager, /. Gen. Physiol., 1940, 23, 561. 



4. L. Golberg, B. de Meillon and M. Lavoipierre, /. Exp. Biol., I945. 



21, 90. 



5. H. E. Martin and L. Hare, Biol. Bull. Woods Hole, 1942, 83, 428. 



6. G. Fraenkel and M. Blewett, Nature, 1943, 151, 703 ; Biochem. J., 



1943, 37, 686. 



7. G. Fraenkel and M. Blewett, Nature, 1943, 152, 506. 



8. M. Blewett and G. Fraenkel, Proc. Roy. Soc, B. 1944 132, 212. 



9. P. S. Saima, Indian J. Med. Res., 1943, 31, 165 ; Proc. Soc. Exp. 



Biol. Med., 1945, 58, 140. 



19. ANALOGUES OF PYRIDOXINE 



Pyridoxine Derivatives 



The anti-dermatitic effect on rats of a series of pyridoxine deriva- 

 tives was investigated by K. Unna,^ whose results are summarised in 

 the following table : 



where + indicates a cure in 75 % of the animals after fourteen days 

 and (+) indicates a partial cure. 



342 



