The difficulties encountered by Seidell in this fractioning study have led
him to adopt Walsche's idea that vitamines are of the nature of enzymes
and hence present all the difficulties of identification and isolation of
those substances.
During 1920 Myers and Voegtlin attacked the problem. They have made a
discovery that is useful as a separatory process. This that the "B"
vitamine is not only soluble in water, but also olive oil and in oleic
acid. By shaking an autolysed yeast extract with those solvents in the
proportion of 1 cc. of solvent to which 4 cc. of extract the vitamine
passes into the oil. When this activated oil is filtered and taken up with
eight to ten volumes of ether it in possible to concentrate the ether
extract in vacuo and extract from it with 0.1 per cent. HCl an active
fraction. Aside from this observation however nothing further has been
reported and the possibility of this method of concentration remains yet
to be exploited. They did report other methods of fractioning which
yielded crystals but failed to produce a pure active substance. Those
results add nothing to what has been previously reported except a new
method of fractioning and the elimination of the following substances as
contributing nothing to vitamine activity (purines, histidine, proteins
and albumoses). The crystals they obtained wore contaminated with
histamine.
The World War has prevented full knowledge of the work of the German
investigators but nothing has appeared that indicates any progress in this
field with the exception of a paper by Aberhalden and Schaumann and some
work by Hofmeister. The Aberhalden paper yields no new data of any moment
and no active substances in pure condition are reported. The reports from
Hofmeister are to the effect that he has isolated a very active solution
belonging to the pyrimidine series. It yields a crystalline hydrochloride
and double salt with gold chloride and has given it the formula
C_5H_11NO_2.
The author ban recently been able to obtain a concentrate vitamine from an
extract of alfalfa or autolysed yeast with the aid of a carbon specially
activated by McKee of Columbia University for the adsorption of basic
substance. This adsorbent has been found quite as effective as the
fuller's earth and it is possible to recover the vitamine from the carbon
with treatment by acid. Glacial acetic and heat are especially favorable
for this process. The study of this concentrate has not, however, yet
reached a stage where it contributes any real data on the subject but
merely provides another method for forming concentrates.
If we were to characterize the present status of the search for the "B"
type it might be said to have resolved itself into obtaining concentrates
of high potency as the first step in the process and this type of
investigation is now going on in many laboratories.
Public-domain text, read in full here on John Shaqi.
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