332 BIOLOGICAL EFFECTS OF RADIATION 



weeks Windaus and Liittringhaus (98) regarded these two preparations 

 as distinct forms of vitamin D and called them vitamin Di and vitamin 

 D2, respectively. Presently, however, Windaus, Linsert, Liittringhaus, 

 and Weidlich (97) discovered that the Linsert preparation was essen- 

 tially identical with Bourdillon's pure calciferol, while the first German 

 preparation was an addition compound of calciferol with an inactive 

 sterol. 



5. Toxisterol. Substance 248. — Morton, Heilbron, and Kamm (61), 

 extending the work of Pohl (64), showed that when ergosterol is irradi- 



o 



ated, the three bands with maxima at 2935, 2820, and 2700 A disappear, 



o 



while a single new band of great intensity develops at 2470 or 2480 A, 

 and in turn fades away to weak general absorption in the far ultra-violet 

 region. With inadequate biological evidence, the assumption was easily 

 made that the new band represented vitamin D. Bills, Honeywell, and 

 Cox (12), introducing precision methods of assay, showed that the 

 appearance of the hand at 2480 A coincided not with the development, hut 

 with the destruction, of antirachitic potency. They, and also van Wijk 

 and Reerink (88), associated substance 248 with isoergosterol. Cox 

 and Bills (21) contributed further evidence of relationship to the iso- 

 ergosterols, but noted a point of difference, namely, that substance 248 

 does not precipitate with digitonin. 



Substance 248 has not yet been isolated. Bills, Honeywell, and 

 Cox (12) found that irradiation products withdrawn for examination 

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

 still contained some vitamin D. Further irradiation totally eliminated 

 antirachitic activity, while only a small amount of substance 248 was 

 destroyed. Laquer and Linsert (51) attributed a toxic quality to sub- 

 stance 248, and proposed the name, Toxisterin (toxisterol). The product 

 which they investigated still contained some vitamin D, but not enough 

 to account for the relatively great toxicity. It was evidently a mixture 

 similar to that which Hoyle (42) obtained by limited overirradiation, 

 and which he reported to have toxic-calcifying properties all out of 

 proportion to the antirachitic potency. Such a mixture, unfortunately, 

 seems to have been the "vitamin D" of the I.G. Farbenindustrie Aktien- 

 gesellschaft patent of 1928 (the old Vigantol of toxic repute). There is 

 considerable evidence, both spectrographic and toxicologic, that toxi- 

 sterol is formed most readily when alcohol is the solvent in which the 

 ergosterol is irradiated (Bills, Honeywell, and Cox, 12, 13; van Wijk 

 and Reerink, 88; Dixon and Hoyle, 23; Hoyle and Buckland, 43; Hoyle, 

 42; Kern, Montgomery, and Still, 47. 



6. Suprasterol I. — C28H43OH; |j; m.p. 104°; general absorption 

 below 2500 A; [a]^' = -76° in chloroform. 



7. Suprasterol II. — C28H43OH; |7; m.p. 110°; general absorption 

 below 2500 A; [aVJ = -1-62.9° in chloroform. 



