364 SECTIONAL TRANSACTIONS.—B. 
will also be made of the action of maleic anhydride upon ergosterol and the effect of 
removal of water from the ergosterol molecule. These subjects will be discussed 
from the point of view of the constitution of this sterol. 
The formation of the isomers of ergosterol under various conditions will be dealt 
with. These include the action of hydrogen chloride upon ergosterol, the treatment of 
ergosterol with finely-divided nickel, and the effect of heating the sterol with sodium 
ethoxide at 200°. Isomerisation of ergosterol can also be brought about by the 
action of ultra-violet light, whereby a number of compounds are formed ; of these 
at least one possesses outstanding importance in virtue of its being the antirachitic 
vitamin. 
Consideration will be given to the process of irradiation and the compounds thereby 
produced. Their physical and chemical properties will be compared with ergosterol, 
and an interpretation of the photochemical reaction whereby vitamin D and the 
products arising from over-irradiation are formed will be attempted. 
Dr. E. H. Reertnx and Dr. A. van W13K.—Isolation of a Crystalline 
Antirachitic Reaction-Product from Irradiated Ergosterol. 
It is possible to obtain a crystalline reaction-product from irradiated ergosterol 
in the following way: ergosterol, dissolved in pure peroxyde-free ether, is irradiated, 
under complete absence of oxygen and under good conditions of stirring, with ultra- 
violet light, from which wave-lengths below 284 my are excluded. The irradiation 
is stopped when about 25-30 per cent. of the ergosterol have been transformed. The 
unchanged ergosterol is eliminated by recrystallisation from ether and alcohol, while 
residual traces may be precipitated with digitonin. All operations have to be 
performed in vacuo. Aiter evaporation of the last solvent the reaction-product is 
obtained as a white crystalline mass. i 
It has been proved that this isolated reaction-product is not stable in solution 
in vacuo ; accordingly, its physical properties vary somewhat with the exact condition 
of the procedure of the isolation (e.g: the duration and the temperature), and do not 
tally exactly with those calculated from the mixture of ergosterol and reaction- 
product immediately after irradiation. The antirachitic activity, however, has not 
perceptibly changed. The melting-point is generally 115°-117°, and the substance 
very rapidly oxidises in presence of oxygen. ‘The possible relation of this substance 
to the crystalline preparations recently obtained in the National Institute for Medical 
Research, and by Windaus, is discussed. 
Prof. I. M. Heirpron, F.R.S., Dr. F. 8S. Sprina, Dr. D. G. WiLKinson, 
and Mr. J. C. K. Stmpson. 
A series of ergosteryl ethers has been prepared and is described. ‘The absorption 
spectrum of methyl ergosteryl ether is identical with that of ergosterol itself, but on 
irradiation it fails to produce an antirachitic product. 
ConcLusion or Discussion by Prof. R. Ropinson, F.R.S. 
Monday, September 28. 
Symposium on The British Fuel Problem, by Sir Davip Mitnu-Watson 
(Coal), Sir Jonn Capman (Oil), and Mr. H. T. Tizarp, C.B., F.R.S. 
(Future possibilities). Sir James C. Irvine, F.R.S., and Prof. W. A. 
Bong, F.RB.S. 
Tuesday, September 29. 
Discussion on The Structure of Simple Molecules. (Introduced by Prof. 
P. DEBYE.) 
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