II. CHEMISTRY 199 



In 1927 Morton et al.,~^^ extending the work of Pohl,^" showed that when 

 ergosterol is irradiated its characteristic absorption l)ands disappear, and 

 a single new band of great intensity develops at 247 or 248 m/x, which in 

 turn fades away to weak general absorption in the far ultraviolet region. 

 With inadequate l)iological evidence, the assumption was easily made that 

 this new band represented vitamin D. Smakula,^^^ however, concluded that 

 substance 248 was not the \'itamin. Bills et al.-^^ showed that the appear- 

 ance of the band at 248 m/x coincided not with the development, but with 

 the destruction, of antiricketic potency. They, and also van Wijk and 

 Reerink,^"^ associated substance 248 with isoergosterol. Cox and Bills^"^ 

 contributed further evidence of relationship to the isoergosterols, but noted 

 a point of difference, namely, that substance 248 does not precipitate with 

 digitonin. 



Bills et al.^^^ found that irradiation products withdrawn for examination 

 at the moment when substance 248 was at its maximum concentration still 

 contained some \dtamin D. Further irradiation totally eliminated anti- 

 ricketic activity, while only a small amount of substance 248 was destroyed. 

 Laquer and Linsert*"^ attributed a toxic quality to substance 248, and 

 proposed the name Toxisterin (toxisterol). The product which they in- 

 vestigated still contained some vitamin D, but not enough to account for 

 the relatively great toxicity. It was evidently a mixture similar to the one 

 which Hoyle^"^ obtained by limited overirradiation and which he reported 

 to have toxic-calcifying properties all out of proportion to the antiricketic 

 potency. Such a mixture, unfortunately, seems to have been the "vitamin 

 D" of the I. G. Farbenindustrie patent^^^ of 1928 (the old Vigantol of toxic 

 repute). The claims of this patent, and of the corresponding American 

 patent,^!^ call for the irradiation of ergosterol to be continued just until 

 the absorption spectrum of what is now recognized as toxisterol attains its 

 maximum ! The mistake was clearly the result of assuming, in the absence 

 of proper bioassays, that the spectrographically most conspicuous irradia- 

 tion product was the vitamin. There is considerable evidence, both spectro- 

 graphic and toxicologic, that toxisterol is formed most readily when alcohol 

 is the solvent in which the ergosterol is irradiated. ^^s. 239. 306. 309, 312 



The purest described preparation of toxisterol is that of the Linsert 

 (Farbenindustrie) patent^"^ for isolating, from the irradiation products of 



'"« A. van Wijk and E. H. Reerink, Nature 122, 648 (1928). 



307 W. M. Cox, Jr., and C. E. Bills, ./. Biol. Chem. 88, 709 (1930). 



3»8 F. Laquer and O. Linsert, Klin. Wochschr. 12, 753 (1933). 



'"9 J. C. Hoyle, J. Pharmacol. Exptl. Therap. 40, 351 (1930). 



"0 I. G. Farbenindustrie Aktiengesellschaft, British Pat. 296,093 (1928). 



'" W. Zimmermann and W. Frankenburger, U. S. Pat. 1,896,191 (1933). 



3>2 W. E. Dixon and J. C. Iloyle, Brit. Med. J. 2, 832 (1928) ; L. J. Harris and T. Moore, 



Biochem. J. 22, 1461 (1929); J. C. Hoyle and H. Buckland, ibid. 23, 558 (1929); 



R. Kern, M. F. Montgomery, and E. U. Still, /. Biol. Chem. 93, 365 (1931). 



