362 SECTIONAL TRANSACTIONS.—B. 
(as 15 per cent. of cod-liver oil). The capacity of the animal for absorbing reserves 
of vitamin A has been found to be extremely high, the limit reached being about 
190,000 B.U. for the entire liver, or about a century’s supply assuming utilisation at 
a rate equal to the minimal curative dose. The individual liver oils sometimes gave 
colour values as high as 600 B.U. per mg. After saponification and the removal of 
crystalline matter concentrates were obtained having values of 2,000 B.U. per mg. in 
the case of the rats fed with red palm oil (biologically active at 0-001 mg.), or 
1,200 B.U. per mg. in the rats fed with cod-liver oil. A point of interest lies in the 
constancy of the final values obtained, which did not seem to be affected by the 
individual values of the various samples before saponification, even when these 
were widely divergent. Some hope may therefore be entertained that the vitamin 
at least presents a considerable constituent of these preparations. Experiments on 
a larger scale, using pigs, have now been started. 
The above results shed some further light on the changes which must occur when 
carotene is converted to vitamin A by the animal. Since carotene has a colour 
value of only about 200 B.U. per mg. it must be implied that conversion is accompanied 
by at least a tenfold increase in colour value. On the other hand, it does not seem 
necessary to assume that the spectroscopically different colour units given by carotene 
and the vitamin must bear the same relation to biological activity. As far as could 
be judged from a limited number of tests the best concentrates were not more than 
2-3 times as active as crystalline carotene. 
Prof. J. C. DRuMMOND. 
Prof. I. M. Heripron, F.R.S. 
AFTERNOON. 
(b) The Chemistry of Vitamin B and Related Problems. 
Prof. B. C. P. JANSEN. 
The method by which Dr. Donath and I isolated the anti-neuritic B, vitamin 
was the following :— 
One hundred kg. of rice-polishings were extracted by water ; the dissolved vitamin 
is adsorbed by 3 kg. of acid clay ; from this it is eluted by baryta. This solution is 
acidified and successively treated by silver nitrate and baryta, by phosphotungstic-acid 
and, in alcoholic solution by an alcoholic solution of platinum-chloride. After 
decomposing the platinum-precipitate the solution in absolute alcohol is fractionately 
precipitated by acetone; after several fractionations we got 30 milligrams of pure 
B,-vitamin-hydrochloride; 100 kg. of rice-polishings contain about 1} gram of 
B, vitamin ; while our procedure gives after several months’ work only 30 milligrams, 
so I tried to improve the method. Phosphotungstic-acid was substituted by the 
more specific silico-tungstic-acid. As Peters first showed, fractionating with silico- 
tungstic-acid gives a much better output. The decomposed platinum-salt may be 
further purified by gold-chloride (Drummond). Seydell and van Veen remove many 
impurities by benzoylation. 
Prof. R. A. Peters.—The Vitamin B Complex. 
This summary is an account of work by Messrs. H. Barnes, J. R. O’Brien, C. W. 
Carter, R. B. Fisher, N. Gavrilescu, H. W. Kinnersley and Dr. V. Reader. 
To solve the chemistry of the vitamin B complex, we must know how many com- 
pounds can be isolated from it, which exhibit independent physiological actions. At 
this stage it seems premature to consider whether such factors have quite different 
chemical structures or whether the independent activities are due to different chemical 
groupings attached to the same nucleus. Estimation of B, may be influenced by the 
presence of other factors ; in the rat by B, (and to a less extent, Bs), and in the pigeon 
by B; (and perhaps B;). B, is concerned with lactic acid metabolism, and the lowered 
brain oxidation in its absence appears to be restored by addition of B, in vitro, pro- 
viding thereby hope of an in vitro test. Yeast B, concentrates curing pigeons and rats 
Ee 
