(Burness). 5 . ~Ieer~vein-Ponndorf lieduction and Oppenauer Oxidation, Bersin (Webster, Cramford). 6. Use of Biochemical Oxidations and Reductions for Preparative Purposes. Fischer (Cran-ford, Webster). 7. Substitution Reactions of .%liphatic Coniponntls. Selles (Bachm:tii). 8. Organic Fluorine Compounds, Bockemuller iI- and rather weak in comparison with the others, hut, t h a t impression was caused. perhaps, by the rather large area which Selles attempted t o cover in t h i r t y pages. On t h e n-hole, the revieivs are very good a n d are well documented, p x t i c u l n r l y lvith reference t o t h e patent literature; the authors are all meil of prominence :ind of outstanding accomplishment in chemistry; and the book useful suppleineiit t o t h e iiiatcrial already avnilable in English. T h e bnok-making is first, rate, t h e paper and typography are excellent, and the binding is good. l‘hcre arc tlvo indcxes-one by subjects a n d tlie other by names of conipounds.
LEE IRVISSXITH. Volumetric A ~ ~ 2 ? / s i sT701. . Z I . T i t i ~ a i i oJletisods. ~~ B y I. 31. 1-of skim milk and the effect of heat treatment thereon. which is shomm t o he related to clianges in the cnseinnte niicelles and t o drnntur:Ltioii of th(, seruni proteins. T h e second half of Eilers’ p i p e r deals with the behavior of sliini inilk o i l concentration 110th xi-itli antl without additioii of sugar. 1-iscosity a n d t h e distri1)utioii of phosphate :tnionp tlie phases are emphasized particularly. Saal’s paper o i i osidatioii-retluctioii p o t e n t i d is a relatively short (30 pages) discussion of t h e components detrriiiining t h e potential, of factors affecting i t , antl of the relation of changes in the p o t e n t i d t o the development of oxidized flavors i n milk. Os>-gen a ~ i d ascortiic :xid are the priiicipal compoiieiits detrriniiiing the potential inrerage f0.27 v.) of fresh raw inilk. Reducing substances formed on heat treatnirnt lower the potential, while addition of copper or iroii salts increases it ivith :t eonconiitiunt developn1ent of oxidized flavors. B u t t e r plasma has u high potential but there is no relation betn-een t h e potenti:il of t h e plasma a n d t h e flavor of t h e butter. Tan der Wawden discausses the development of storage flavors in butter, presenting evidence t h a t , contrary t o t h e generally accepted ideas, fishy flavors in storage butter arise from oxidative processes rather than from hydrolysis of lecithin t o trimethylamine. Tlie materials responsible for t h e off-flavor were prepared in a highly concentrated form b u t could not be isolated a n d identified. T h e relations of forniation of perosides and of partition of copper a n d iron aniong t h e phases of butter t o the developnient of off-flavors were found t o substantiate t h e hypothesis t h a t the flavors are caused b y osit1:ttive processes. I n general, the book is n-ell organized a n d fairly well written. Certainly it rontains it large amount of information which is of interest t o workers i n the fields covered. T h e lack of access t o foreign literature after 1940 is evident, particularly in regard t o t h e discussion of milk serum proteins a n d oxidation-reduction potential. T h e book contains n consitier-
+
~
