JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS my mind that the very smell of the earth, in which we all delight, the smell which fills the air after rain in summer, and is strong when we turn up a spadeful of fresh mould, which the rustic calls "good," believing, perhaps rightly, that we must smell it every day to be well and live long, is yet after all, an odour given off by a living thing--Cladothrix 'odori- fera--too small for human eyes . . . yet they are able to find a passage to us through the other subtler sense and from the beginning of our earthly journey even to its end, we walk with this odour in our nostrils, and love it .... " It would seem, however, that Dr. Hugh Nicol has assembled most of the references to the scanty litera- ture on this subject, in an article published in 1933 and a later contri- bution entitled "The production of odorous substances by the aid of micro-organisms.' ,4 These papers con- tain many items of interest to the thoughtful perfumer. The second contribution mentions that the basic earthy odour has been ascribed to .the Actinomycetes (or ray-fungus), but I think the point of outstanding interest is that dealing with the .fungal decomposition of glucose, resulting in the production, not only of ethyl acetate, but of other sweet, ethereal "woody and autumnal" esters. In practical perfumery, the earthy odour may perhaps be best described as a blend of the oakmoss fundamen- tal, with a moderate ferny undertone which includes a trace of a sweet fungal element. Light touches of 192 such bases add a desirable similitude of naturalness to folial compositions, and these in their turn can be used to impart a distinctive tonality to cyclamen, gardenia, mignonette, muguet and tuberose compositions. In so far as synthetics are con- cerned, an unmistakably earthy odour is associated with iso-butyl quinoline and linalyl-heptyl ether, and this is even more evident when they are blended with fenchyl alcohol but the approach to the odour of freshly turned earth can be simulated with greater fidelity by incorporating such elementary bases with anethole-containing oils such !, as dill or fennel, shading with basil, :: pennyroyal, rue and sage, and add- ing, as a final touch, a little of a ß: rhodinol fraction exhibiting the char- acteristic wet-straw note. THE F-UNGAL AROMA This term needs a little clarifying,.'::: because the natural odour varies.: . from the pleasantly culinary (and sometimes perfumed) aroma of the edible mushrooms to the unpleasanti:: I dankness of the poisonous toadstools ' we have also the s.ickly sweetnessi' exhibited by .many types of mildew: " and the sour or vinous "secondaryl .. fermentation" odour associated with: various moulds. Furthermore, there is a wide:i .: diversity in these aromas in the fresh ::i• and damp stage as compared with?if_! those of the humus or air-dried?i? spores, but from the perfumery view-..[?i point it is probable that the pleasanti',7i Champignon prototype is found tø?-i :!

•,st advantage in the cyclic ethylene- :ol acetal of hydratropic aldehyde in the cruder and heavier note the di-methyl acetal. Upon careful selection, however, it•.i.•is found that there are quite a of the medial aliphatic which may be used in con- .•. •junction with the hydratropic and :i)'•?heptaldehydic acetals, particularly !•j•ithe secondary hexyl and nonyl ?i:i'i:"a'Cetates while, for example, definite :!i?'i'shadings can be borrowed from the i ii-i 0ur-earthy note of hexyl propionate, ?the'sweet mushroom-honey tone of •'i}i/6Ctyl propionate, the secondary- :i •.:!'fermentation fragrance of phenyl- i:i!ethyl caprylate,' the more floral, 'i:-iUngal-gardenia undertone of n- •.•:il n0nyl and n-decyl acetates and the 'i)11iPeculiar fungal-rose-orange complex ::•' of nonyl caprylate. ß •:•':'::•.:: The usage of such sweet, sickly :::i: bases is, as already indicated, that of an embellishment of the mossy ::and folial undertones, so that for i: :•. )ractical purposes in perfumery, :. i:fungal and earthy tones can be :.i•'regarded almost as synonyms. THE ROOTY COMPLEX : i The rhizomic odour would appear to be a composite note based upon :various proportions of the damp aroma associated with ferns, earth and fungus, with the peculiar dry and somewhat astringent tones of friable or crumbly earth, which in itself has a ligneous or powdered- bark back note. In this group the synthetic adju- rants play a comparatively minor PERFUMES role, as the odour of wild parsnip- seed oil epitomises the fernyoearthy- fungal tone, and this gives better results than items selected from the comparatively narrow gamut of octyl and octyl-crotonyl acetates, buryrates, propionates and laurates. From such a starting point, how- ever, via the oakmoss "esters," the note begins to embrace the lichenol inflection of p-iso-propyl quinoline and the labdanol shading of iso- butyl cinnamate, but from here the balance of the tonal elements must be sought among the natural pro- ducts. Probably the most descriptive adjective which can be applied to the rooty group is "dank," and, if the term can be accepted, then "essence of dankness" is well exem- plified by a blending of galbanum resinoid and immortel (everlasting) absolute, for in the latter is observed something of the liquorice note which contributes largely to fungal sweetness: a similar' sweetening action is also noticed in the inclusion of the perfumed bdellium, sweet myrrh or bissabol opoponax. From another angie of approach, Herabol myrrh, sassafras and asafce- tida exhibit a dry, powdery ligneous astringency, thus beginning to verge towards the woody note, but also from this departure point is seen the advent of aromatic and spicy warmth. via the ginger root, the methyl eugenol background of Canadian snake-root oil, leading to sumbul (musk-root), the musk lactones of angelica root and thence to the violet undertone of costus root and 193