In a previous article, entitled "Light and the Antirachitic Factor," Frans Faber and I1 maintained that the so-called antirachitic factor was not specific, because in addition to the antirachitic effect it also had an activating influence on other functions, and, moreover, that it could not be a vitamin but must be the energy of the ultraviolet rays.
While the antirachitic factor, according to our conception, is not a substance, there is no doubt that the A-body is an actual substance. J. C. Drummond and his collaborators have shown that the A-body is an organic substance which acts as such and not indirectly as a ferment. The A-body does not belong to the lipoid bodies, which I presumed when I first discussed this substance in 1914 and 1916, but, according to a statement of Drummond, the investigator who has gone most deeply into its chemical constitution, it is probably a
BLOCH CE. LIGHT AND THE A-BODY. Am J Dis Child. 1926;31(3):315-322. doi:10.1001/archpedi.1926.04130030002001