METABOLISM 



13. K. W. Cosgrove and P. L. Day, Amer. J. OphthaL, 1942, 25, 



544- 



14. M. K. Gregory, Brit. Med. J., 1943, 2, 134. 



15. I. Mann, Amer. J. OphthaL, 1945, 28, 243. 



16. H. R. Sandstead, U.S. Publ. Health Rep., 1942, 57, 1821. 



17. L. Lehrfeld, Arch. OphthaL, 1944, 31, 557. 



18. H. Scarborough, Brit. Med. J., 1942, 2, 601. 



19. W. M. Fish, BriL J. OphthaL, 1943, 27, 107 ; Amer. J. OphthaL, 



1944. 27, 354. 



20. F. F. Tisdall, J. F. McCreary and H. Pearce, Canad. Med. Assoc. J., 



1943, 49, 5 ; J. F. McCreary, J. V. V. Nicholls and F. F. Tisdall. 

 ibid., 1944, 51, 206. 



21. T. K. Lyle, T. F. Macrae and P. A. Gardiner, Lancet, 1944, 1, 



393- 



22. W. J. Wellwood-Ferguson, ibid., 431. 



23. L. Castellanos, Arch. OphthaL, 1944, 31, 214. 



24. R. Antognini, Schweiz. med. Woch., 1941, 71, 510, 



25. I. J. Boerer, C. E. Stanford and E. Ryan, Amer. J. Med. Sci., 



1943. 205, 544. 



26. K. Braun, Y. M. Bromberg and A. Brzezinski, /. Obstet. Gynec, 



1945, 52, 43. 



II. 2V1ETABOLISM OF RIBOFLAVINE 



Concentration of Riboflavine in Blood 



The blood of man, the rat and the calf were reported ^ to contain 

 0-5 yig. of riboflavine per ml., and that of the dog and pig i-o /xg. per 

 ml. The microbiological assay method of Snell and Strong was used. 

 No attempt appears to have been made to use blood concentrations 

 for assessing the nutritional status of animals or human subjects 

 with respect to riboflavine such as were made with aneurine. Indeed, 

 it has been said that there is no relation between blood concentration 

 and dietary intake in the horse. ^ 



Urinary Excretion of Riboflavine 



Ribofiavine-deficient dogs and rats excreted less riboflavine in the 

 urine than did animals fed a normal diet.^ The fall in excretion was 

 observed before the other symptoms of riboflavine deficiency appeared. 

 Riboflavine can be estimated in urine either by the microbiological 

 method, using L. helveticus,^ or fluorimetrically ^ (see page 157). When 

 the former method is used, a correction must be applied to compensate 

 for the effect of urea, the presence of which tends to suppress the 

 growth of the organism.^ 



A relationship has been shown to exist between the urinary excretion 



12 177 



