152 VITAMIN D GROUP 



TABLE II~Concluded 



c-„_.- Provitamin D, parts per 



^°^^'^^ thousand of total sterol 



Invertebrates — Continued 



Ostrea (Sp.), Australian oyster 130 



Arion (Sp.), black road snail 120 



Myiilus edulis, sea mussel 100* 

 Helix pomatia, edible snail, vineyard snail 97* 



Anodonta cygnea, swan mussel 80 



Ostrea virginica, oyster 80 

 Pecten (Sp.), Australian scallop 65 



Mytilus planulatus, Australian mussel 62* 



Cardium edule, cockle, sand shell 50* 



Cardium tenuicostatum, Australian cockle 41* 

 Ostrea edulis, oyster 34* 



Limax agrestis, earth snail 32 



Sepia (Sp.), cuttlefish, squid 12* 



Echinoderms 



Astropecten irregularis, little sea aster 4.5 



Asterias rubens, starfish, big sea aster 3.8 



" Data from Windaus,^* Gillam and Heilbron,^^ van derVliet,^^ and others. Figures 

 marked (*) are the average of two or more determinations. 



from the organic chemists by Callow, ^^ who first applied it to vitamin D 

 work in the isolation of calciferol from irradiated ergosterol. It has proved 

 useful in the identification of both the vitamins and provitamins D, to which 

 latter purpose it was first applied by Boer et al.^^ Boer was also the first 

 to adapt chromatography to the isolation of a provitamin D, and he gave 

 a good working account of this procedure. 



The unsaponifiable fractions of the fats of nearly all plant and animal 

 tissues (Table II) exhibit the provitamin D absorption spectrum, but the 

 quantity of provitamin D present is usually so small that its isolation is a 

 task of considerable magnitude. ^^ Isolation has been achieved in only a few 

 instances, leaving great territories unexplored. The following examples con- 

 stitute most of the published work to date. 



^2 R. K. Callow, Chemistry at the Centenary (1931) Meeting of the British Associa- 

 tion for the Advancement of Science, p. 149. Heffer, Cambridge, 1932. 



'3 A. G. Boer, E. H. Reerink, A. van Wijk, and J. van Niekerk, Proc. Koninkl. Akad. 

 Wetenschap. Amsterdam 39, 622 (1936) ; A. G. Boer, J. van Niekerk, E. H. Reerink, 

 and A. van Wijk, Dutch Pat. 45,849 (1939). 



9^ A. Windaus, Nachr. Ges. Wiss. Gottingen, Math, physik. KL, Fachgruppe III 

 185 (1936). 



" A. E. Gillam and I. M. Heilbron, Biochem. J. 30, 1253 (1936). 



96 J. van der Vliet, Chem. Weekblad 39, 271 (1942). 



" A. Windaus and O. Stange, Hoppe-Seyler's Z. physiol. Chem. 244, 218 (1936). 



