618 BIOTIN 



egg white or avidin started, will bring about resumption of normal growth 

 in the larvae. ^^ 



D. HIGHER ANIMALS AND MAN 



For reasons previously mentioned it is very difficult and at present 

 barely possible to give a correct estimate for the biotin requirement in 

 animals and man. In the relevant literature the figures given represent in 

 general the recommended minimal daily dose, with wide variations. 



There is a fairly definite but not completely satisfactory correlation" 

 between body weight and daily biotin requirement (per kilogram of body 

 weight) . 



Even if the quantitative daily biotin requirement could be exactly de- 

 termined and defined for a given case, the results obtained would apply 

 only for the condition existing at the time of the observation. Requirements 

 for essential nutrients, and therefore also for biotin, are not rigidly fixed 

 quantities. They vary according to the internal and external environment 

 of man and animals at a given moment. Thus the above figures should be 

 considered as approximations, subject to wide changes and fluctuations. 



" P. S. Sarma, Indiana J. Med. Res. 32, 149 (1944). 



« R. J. Williams, J. Am. Med. Assoc. 119, 1 (1942). 



" E. Nielsen and C. A. Elvehjem, Proc. Soc. Exptl. Biol. Med. 48, 349 (1941). 



"6 G. A. Emerson and J. C. Keresztesy, Proc. Soc. Exptl. Biol. Med. 51, 358 (1942). 



" E. Nielsen and A. Black, J. Nutrition 28, 203 (1944). 



« T. H. Jukes and F. H. Bird, Proc. Soc. Exptl. Biol. Med. 49, 231 (1942). 



^» L. R. Richardson, A. G. Hogan, and O. N. Miller, Univ. Missouri Agr. Expl. Stat. 



Research Bull. p. 343 (1942). 

 50 J. H. Shaw and P. H. Phillips, J. Nutrition 29, 107 (1945). 

 " D. M. Hegsted, R. C. Mills, G. M. Briggs, C. A. Elvehjem, and E. B. Hart, /. 



Nutrition 23, 175 (1942). 

 " H. Patrick, R. V. Boucher, R. A. Butcher, and H. C. Knandel, Proc. Soc. Exptl. 



Biol. Med. 48, 456 (1941). 

 " T. J. Cunha, D. C. Lindley, and M. E. Ensminger, J. Animal Set. 5, 219 (1946). 

 " R. J. Williams, R. E. Eakin, E. Beerstecher, Jr., and W. Shive, The Biochemistry 



of B Vitamins. Reinhold Publishing Corp., New York, 1950. 



