β Scribed by Greenwood, H. W.
No coin nor oath required. For personal study only.
cmulsificntion is still iiicoiiiplctc." h uscful contribution towards such n tlicory is contailled in the first nppcndis, in which l'rof. IV. llniiisilcn givcs liis theory of emulsions stnbiliscd by solid particlcs. Tliis is n subject 1)-liich hitherto has rcccivcd scant attention, which is nll tlic inore surprising in view of its very rcnl iniportancc in tcclinology. l'rof. Raniilcii's theory descrvcs serious considerntion, cspccinlly its cnipliasis on tlic valuc of knowledge of tlic rclationsliip bctivcen thc wctting poivcr of a phnsc and tlic stability of nil cmulsioii. It is nlso rich in suggestions of n o d methods of attacking ccrbnin emulsion problems. Tliis calls to mind onc detail whicli tlic book fails to den1 with, niid tlint is the plasticity of emulsions npproncliiiig or nctunlly of a solid typc. ATcntion is iiiadc on p. 44 of the probletii being untouchcd ; though this is not quite t,lic fact, it is so ncnrly so ns to ciiiphnsise tlic ncccssity for niucli tiiorc cstcntlcd invcst,igntion in this particnlar direction, for it is only by t,he plnstoinctric study of such cinulsions tlint vitally important inforinntion can l)c obtninctl.
Tlic cliaptcrs on ciiiulsificntion and dc-ciiiiilsificatioti arc adcquatc and int.crcstiiig, nlthough oiic might w i d for somcwhat fuller iliscussion of colloid iiiills, if oiily in tlic form of grcntcr details as to prncticnl pcrforinmice. This is ntoucd for, ho\vcvcr, by tlie nuiiicrous csamplcs of cniulsificntion in practice, discusscd in n way which, ivliilc prcscnting tlic cnsc ns it s t n d s t is, t1t tlic sntiic tiiiic, full of saggcst,ioii of applicntiotis to cognntc problcins. IIercin lies tlic kcynotc of tlic book-prncticality. It is cssciitiully n prncticul book for the prncticnl iiinii, ; i d not the least valunblc p u t csists in tlic two nppciidiccs, oiic on cniulsifyiiig ngciits for prcparing tcclinical oil/\*:itcr cinulsions, m i d tlic otlicr 011 thc scparnt,ioii of tccliiiicnl cniulsions. Tlicrc is in addition nn ndniirnblc bibliogrnpliy nud n good iiuthor and subjcct indcs.
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Lo~itlo~i : 0. Udl ck SUM, Ltd., 1OSO. 1%. (id.'l'liis is :I stiniuliiting rind suggestive hook to Ite coniincntlctl to tlic tritincd I)liiiriiincciiticnI :ind iigricultiirnl clirinist . It piirports to bc intcntlcd for 1112ginners, hit is unsiiitnlilc for their IIHC, I)cciiir;c, :is is inevittililc
## OF BOOKS 83 1 oral contraceptives. Professor R. H. S. Thompson's chapter on demyelinating diseases presents a difficult subject in a lucid and readily assimilated form. Other subjects reviewed include recent developments in nucleic acids, sex chromosome anomalies, virus vaccines, the endocrine