: REVIEWS... 
EDIBLE FATS AND OILS, C. Ainsworth Mitchell, B.A., F-1.C., pp. xii + 159. 
Longmans, Green, & Co., 1918, London. 6s. 6d. This book belongs to the series of 
Monographs on Industrial Chemistry, edited by Sir Edward Thorpe; by which it 
is hoped to afford examples of the application of recent knowledge to modern 
manufacturing procedure. Such books are not intended to cover the whole ground 
of the technology of the subject. We have the fine work of Lewkowitsch for that 
purpose. ‘Thorpe’s series are not concerned so much with the minute details of 
- manufacture, so that Mitchell’s book deals with the chemistry and characteristics 
of the oils that can be made edible, and he endeavours to give a description of the 
methods of extracting such oils and fats from the crude material and of purifying 
and preparing them fdr food purposes. To render the book a convenient source 
of reference, foot-notes and an extensive bibliography (pp. 124-151) are given, in 
which both the original reference and the abstract in the English or other journals 
‘are given, and they are arranged according to the subject headings of the various 
chapters. 
_ The first two chapters cover the nature and, properties, composition and con- 
stituents of oils and fats (pp. 1-23), and is a good and up-to-date account of the 
subject. An interesting section deals with the rancidity of fats, a subject in 
which both the butter-maker and the margarine manufacturer are vitally con- 
cerned, Chapter IV. gives a good summary of the methods of examination 
(pp. 35-56). We would like to see some indication, with so many tests, which are 
the most reliable ones for the various oils, e.g., Laucks places the iodine value 
first in his examination of commercial oils. Chapter IIT. covers rather too briefly 
the extraction and purification. Here we find the few illustrations of machinery 
used. The section on Purification (bleaching, deodorizing, and removal of 
rancidity) is too condensed, as it 1s in this part of the work that the main problems 
occur in the commercial preparation of an edible food from the raw material. 
The body of the text gives the details of the individual oils (pp. 57-106). ‘This 
includes tables of typical values to enable one to ascertain the standards of 
purity. The last two chapters deal with Hardened Oils and Manufacture of 
Margarine. While the latter gives some of the more modern types of machinery 
' for the processes of manufacture, the two chapters do not appear to be quite as 
up-to-date as one would expect in such a monograph. Such information should 
have been brought almost to the date of publication. In hydrogenation there 
does not appear to be anything later than 1913, and that in a subject which was 
advancing so rapidly (see Hydrogenation of Oils, by Ellis). The margarine 
Section comes to 1914, There are several references to the presence of nickel in 
hardened oils, but recent English preparations (before 1918) did not contain 
appreciable quantities as stated. ; 
Information is given on aroma production by bacterial cultures, and attempts 
at producing browning properties in imitation of butter; but. nothing is men- 
tioned about the presence of vitamines in margarine. ‘This was one point on which 
the supporters of butter as a food relied when they stated that it contained some 
natural property which rendered it more suitable and more digestible than mar- 
garine. Such statements were recently made in Melbourne before the Board of 
‘Trade, but all recent investigations in America and Europe place properly-manu- 
factured margarine—which does contain vitamines—a point or two ahead of 
butter in. digestibility, and it is much purer and more easily handled since fats 
have been hydrogenated. Food rations, butter tickets, and well-made margarine 
have broken down the English prejudice against margarine; and Australian 
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