276 | Traditional medicineThe volatile oil of the eucalyptus plant (Figure 10.3) was then used for
similar respiratory problems as that of the peppermint plant. The Australian
oil has a much stronger smell than its European counterpart and so was
used in smaller quantities – happily as it turns out because eucalyptus oil is
chemically different from peppermint oil and a great deal more toxic.
Tonics were very fashionable in European circles in the nineteenth
century. These often contained small quantities of quinine or other bitter-
tasting substances and were used to stimulate saliva flow and thus promote
general well-being. Aborigines appeared not to have used their plants for
such purposes but the settlers identified – after some trial and error – that a
number of Australian plants could substitute for remedies used in Europe.
Some plants such as Centaurium spicatumwere ‘pleasantly bitter’; others
such as bitter bark, Alstonia constrica, were much less pleasant leaving a
long-lasting bitter after-taste in the mouth.^6
When the Aborigines were confronted with European diseases they not
only tried their own old remedies and those that the Europeans had brought
with them but also investigated the value of other native plants. A number of
them appear to have been chosen on thesimilia similibus curanturor ‘like
treats like’ principle, one favoured by many cultures in different regions and
at different times. This was especially evident in their choice of some plants
Figure 10.2 Melaleuca(tea tree).