' REQriREMEXTS FOR VITAMIX K 781 



normal within four hours, and maintained the normal level for twenty-four 

 hoiu-s. Although these data do not give actual requirement levels, they 

 are of \'alue in determining minimal dosages. In all eases these are in the 

 microgram range. 



(S) Requirement for Man 



Xo precise figures are available for the vitamm K requirement of man, 

 but it appears to be in the microgram range. Thus, Sells et al.-^'^ reported 

 that a single intramuscular injection of 10 /xg. of 4-amino-2-methyl naph- 

 thol h3'droch]oric acid given at birth almost completely prevents the delay 

 in the prothrombin time during the first week of life. Daily doses of 

 1 ng. were found to be equally effective. Hardwicke-®^ reported com- 

 parable results with the diphosphoric acid ester of menadiol, and Adler-^- 

 also confirmed the effectiveness of dosages of 1 to 5 ng. of vitamin K. 



2M R. L. Sells, S. A. Walker, and C. A. Owen, Proc. Soc. Exptl. Biol. Med., 47, 441-445 

 (1941). 



261 S. H. Hardwicke, /. Pediaf., U, 259-269 (1944). 



262 B. Adler, .}ronntschr. Geburtschiilfe u. GynakoL, 118, 225-248 (19441 



