of time to permit the establishment of the is still a matter of debate and hence the true vitamin value of any foodstuff. tests for this factor are as yet unsatisPending the isolation of each vitamin and factory. an accurate method of assay, we must When we consider that the existence of develop the biological test to as high an vitamins was unknown less than 16 years accuracy as possible. It would extend ago, the outlook for proper assay of these this paper too greatly to review the story factors is encouraging in spite of the of measurement of vitamins D and E. limitations we have noted. Owing to the sharpness of the pathological picture, D measurements are fairly REFERENCES satisfactory, but little data has yet been 1. Sherman & La Mer, & Campbell. J. Am. Chem. Soc. 44:165, 1922. obtained. Hess has reported a general 2' Lewis, H. B. J. Biol. Chem., 40:91, 1919. absence of D in green vegetables tested, 193. Drummond and Coward. Biochem. J., 14:661, such as lettuce, spinach, etc. We have 4. Zilva and Miura. Biochem. J., 15:654, 1921. confirmethis finding in the case of peas. 5. Sherman and collaborators. J. Am. Chem. Soc., confirmed tnls nnalng ne case OI pea47:1639-1662, 1925. We have not yet tested bananas for this 6. Sherman and Munsell. J. Am. Chem. Soc., 47:1634, 1925. Hazel Munsell; Dissertation, Columbia factor. The very existence of vitamin E University (1924).