llecolrell ltny 13.1940 'J.S.C.I. l!M, 63, :Ul 4* r.-r f , .J,I.). )07 J Ilrnclley nntl Purr, Clicni. JIet. Eiig. l D E , 27. 737 I)rinklinmnirr, lirnwn nnd White. Trnns. tinier. Inst. C l i m i . Eng. 1945, INSECTICIDES : CHEMICAL CONSTITUTION AND TOXICITY* By HUBERT MARTM Of tlio severnl ways of stiitlying the relntionsliip bct\vrt*n iiiolccnlur stnicturc ant1 toxicity, tlic iinalyticnl iiictliotl, wlieii effects of modilicntioti and dissection of tho molcculc ire followctl, is applicnble to insi-rticidcu of iiisignificnnt. nipour prcasiire nt ordinary tcwiperntnrcs. Tlir rlfect of ' modification of the iiioIcciiInr atruetiircs of nicotine, rotenoni., nnd of the ~'yretliriii-synergists ullictl to acsaniin on tlicir insccticidnl propertica ia ilisciiasetl. Tlie iniprtunce of pliyairnl prolwrtiex nffectiiig the distribution of tlio insccticirlu betwetvi the bioplinss in wliirli it ncts iincl tlir Iihiise in which it is upplied is ilhistrnted by the eiisi' of tlic nliplintic thiocynnntm. Tlie reasons why DIYP ia ineceticirliil nrc clisciisscd nnd it is aliown tlint tlic possibility of rendy tlrliydrocliloriniitioii is rcqnisitt* for insccticicllrl 1mqxxtit.s in tliis series, i i n iden now exlcntled to otlrer rlilorinntetl Iiyclrocnrbons.