C. A. ELVEHJEM 



in the presence of fat. There is much evidence to show that fat, carbo- 

 hydrate, protein, and vitamins are all interrelated in their effect on the 

 production of both known and unknown vitamins in the digestive tract 

 of all animals; but the results for one animal cannot be predicted from 

 the results obtained with another species. Just where the human fits 

 into the picture is impossible to say. It is encouraging to find that 

 several groups of workers are engaged in studying this problem on 

 human subjects, a project which will undoubtedly clear up many of the 

 difficulties now encountered in attempting to establish quantitative 

 requirements for each of the vitamins in human subjects. The final 

 answer can probably be made only when animals are rendered bac- 

 teria-free and their requirements are studied under these conditions. 

 Although this will answer the questions from an academic point of 

 view, for practical purposes we must continue to recognize the inter- 

 relationship of food and intestinal bacteria. No one need feel that 

 further work in the field of vitamins will not be productive. Much 

 human suffering has been alleviated through our knowledge of vita- 

 mins and we can expect much success in the future if we learn more 

 about these interesting compounds and if we apply what we learn in a 

 sensible manner. 



Selected References 



Addinall, C. R., "Synthesis and production of vitamins," Chem. Eng. News, 



22,2174 (1944). 

 Black, J. D., ed., "Nutrition and food supply: The war and after," Ann. Am. 



Acad. Political Social Sci., 225 (1943). 

 "Enrichment of flour and bread. A history of the movement," Bull. Natl. 



Research Council, No. 110 (1944). 

 Evans, E. A., Jr., ed., Biological Action of the Vitamins. Univ. Chicago Press, 



Chicago, 1942. 

 Major, R. T., "Industrial development of synthetic vitamins," Chem. Eng. 



News, 20, 517 (1942). 

 "Medical survey of nutrition in Newfoundland by a group of investigators," 



Can. Med. Assoc. J., 52, 227 (1945). 

 Rosenberg, H. R., Chemistry and Physiology of the Vitamins. Interscience, New 



York, 1945. 

 Schultz, T. W., ed., Food for the World. Univ. Chicago Press, Chicago, 1945. 

 Williams, R. R., and Williams, R. J., "Vitamins in the future," Science, 



95,335-344 (1942). 



88 



