20 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 1 Preparation of test compounds (key in page 21) arranged isomers, representing in each case the d-alpha, d-beta, 1-alpha, 1-beta derived compounds. The panelist was asked to pair the four blotters according to quality, and then to repeat his classification without being told what result he had obtained. Each selection was weighted equally. In a supplementary test, in which the final evaluation was a triangle test, three samples of "hydroxy citronellal" (2, 6-dimethyl-octan-2-ol-8-al) were presented with the panelist being instructed to select the "odd" sample.

ODOR AND OPTICAL ACTIVITY 21 Id Tl-•d I i d-• Pinene Trd I © t-• Pinerie-... TTt t-a Pinene--,--[t-a Pinene epoxlde],• :•t 'rlTl Pinocorvyl I • propionate .SZ:da !__1© j • Pinoco rveol IL•,-J•,Myrtenøl •) Pinoacetoldehyde I '•' d•, Pinocorvyl I • propionate i • Myrteno_l • Myr. te. nol Pinocarveol 3) • oce,o, •z• d• I T•d• I Pinoacetaldehyde. _ I Pinocarvyl propionote • •,• . t Pinocorveo•11 L• '}.__..i (:i ) Myrtenol_ I _l•..Myrtenol • L• •oceto• ¸ Pinoacetaldehyde Pinocarvyl • propionate (D (D © • ocetol.o•iT 3•- I.a Pinocarveol •Trr ta L ! • Pinoacetaldehyde Key •co Fig. 1 The three materials were derived: (1) From /-citronellol ex/-pinene via/-pinane and/-dihych'o myrcene. The citronellol was hydrated to 2,6-dimethyl octan-2, 8-diol, which was oxidized to l rotatory "hydroxy citronellal" (4, 5). The distilled product was prep-trapped to 98% purity. (2) From d-citronellol, ex d-citronellal from citronella oil. The same hydration, oxidation and trapping procedure gave d "hydroxy citronellal" of 98% purity with practically the same glc pattern for the remaining impurities as in (1). (3) From d-citronellal ex citronella oil by the standard hydration pro- cedure via the bisulfite addition compound. The final 98% trapped material had a glc pattern differing from those of (1) and (2). In spite of the similarity of the glc patterns of (1) and (2), and their dissimilarity to that of (3), the panel test, conducted with experts, resulted