RECENT DEVELOPMENTS IN ESSENTIAL OILS 305 sesquiterpene alcohol viridiflorol, m.p. 73-75 ø, together with cineole, terpenes, terpineol and sesquiterpenes. In some cases these latter oils contained so much viridiflorol that the crude oils solidified after distillation only a small percentage of cineole was present. An inverse ratio appeared to exist in the quantities of viridiflorol and cineole in such oils a low viridiflorol content seems to be associated with a higher cineole content, these oils approaching cajuput oil in general characteristics. (7) Zieria smithii Andrews. Examining the essential oils of the shrub Zieria smithii (faro. Rutaceae) Morrison, Penfold and Simonsen (103) noted that considerable variation in oil composition may be expected. The following compounds have so far been identified in these oils: safrole, methyl eugenol, elemicin, (+)-o•-pinene, (-)-zX•-carene-5,6-epoxide, lina- lool and eugenol. The phenol ethers occur alone or in admixture, in some cases all three occurring together. In some oils, one of these particular phe- nol ethers--safrole, elemicin or methyl eugenol--may occur to the extent of 80 to 90 per cent. II. Biosynthesis Studies Fascinated by the success obtained in tracing the biosynthesis of ter- penoid compounds by means of radioactive isotopes, Penfold and Willis (126) recently published a review of current experiments which attempt to trace, with the aid of radioactive acetate, the natural synthesis of citro- nellal by Eucalyptus citriodora. The potential value for biosynthesis stud- ies of such a series of physiological (orms as those of Melaleuca bracteata appears obvious, and an outline of proposed experiments is given. McKern, Spies and Willis (94) reveal another line of attack in their critical studies on variations in essential oil yield, and composition within and between indi- vidual trees of various eucalypt species. By applying standard techniques of sampling and distillation, it has been shown that the piperitone content of Eucalyptus dives oil rises as the leaves mature, apparently at the expense of the hydrocarbons. IlL General Research on/lustralian Essential Oils The essential oil of Baeckea crenulata De Candolle has been investigated by Penfold and Morrison (118) it consists principally of (d-)-o•-pinene, (d-)- and (+)-limonene, 3,-terpinene, p-cymene, linalool, sesquiterpenes and baeckeol. The oil was obtained in yields ranging from 0.2 to 0.36 per cent terpenic constituents accounted for about 85 per cent of the oil. Myoporum crassifolium Forst. ("Anyme") is a small tree endemic to New Caledonia, the wood oil of which was shown to consist chiefly of a sesquiterpene alcohol identical or isomeric with bisabolol (113). Later investigations (112) confirmed this sesquiterpene alcohol as a stereoisomer of bisabolol.

306 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Birch, Mostyn and Penfold (23) investigated the cause of the low specific gravities occasionally experienced in Western Australian sandal- wood oils (Eucarya spicata Sprague & Suture.). Such oils were found to contain considerable percentages of farnesol. The structure of angustifolionol, a yellow crystalline substance (m.p. 118 ø) isolated by Penfold from the essential oil of Backhousia angustifolia Benth. has been studied by Birch, Elliott and Penfold (21) angustifolionol is actually 5-hydroxy-7-methoxy-2,6,8-trimethylbenzochromone. In the same paper these authors also discuss the biogeneric significance of this compound. Baeckea critriodora, a new species of the fam. Myrtaceae, was recently de- scribed by Penfold and Willis (125). The essential oil occurs in the leaves to the extent of 0.33 to 0.74 per cent. Penfold, et al. (115), found it to con- sist principally of (+)-citronellal (54 to 80 per cent). Minor constituents are isopulegol, (+)-a-pinene, citronellol and small amounts of esters. RECENT DEVELOPMENTS IN ESSENTIAL OIL PRODUCTION ztrgentina Although Argentina is a country highly favored by nature from the agricultural point of view, its essential oil industry has remained relatively small and confined to the supply of the domestic market. At the present time Argentina produces per year approximately 80,000 pounds of pep- permint oil (Mentha piperita) (172), 50,000 pounds of mint oil Japanese type (Mentha arvensis), 30,000 pounds of lemongrass oil, 20,000 pounds of citronella oil, 25,000 pounds of lavandin oil, 25,000 pounds of anethole (isolated from fennel oil), 30,000 pounds of eucalyptus oil (Eucalyptus globuIus), from 5000 to 80,000 pounds of guaiac wood oil (the quantity varying greatly and depending upon the demand from abroad), 30,000 to 40,000 pounds of sweet orange oil, and increasing quantities of lemon oil (actual figures are not available). Undoubtedly, as the population of Argentina increases, production of essential oils will expand to meet the domestic requirements. There is a good possibility that in the future some oils will also be exported. Brazil As in most other agricultural activities, Brazil offers possibilities also in essential oil production, although they have not yet aroused much in- terest among landowners. The reason is simply that other and much bet- ter understood crops (coffee, cocoa, tobacco, cotton, cereals, sugar, etc.) promise larger, easier and safer returns than essential oils, which require a great deal of experience, know-how in distillation, etc. Moreover, agri- cultural labor in Brazil is no longer abundant and low priced, and in the