62 



as Rutaceae, which is marked by many odours, some- 

 pleasant, many otherwise, and all of an abominable taste, 

 commended itself greatly to the credulous. Any dis- 

 turbance of the functions, if it did not kill, was supposed 

 to be of benefit. There is little doubt that as far as mere- 

 disturbance is concerned, this family is eminently suited 

 to do that. But the more scientific the medical profession 

 has become, the more has it lost faith, till now the greater 

 number of the nasty-tasting herbs are left alone. In any 

 family producing aromatic oils, such as this and the 

 Myrtles, the production never appears to be confined to 

 one oil. Each species, or group of closely allied species^ 

 certainly construct the same, and that without any refer- 

 ence to the soil in which the plant lives; thus, Pepper- 

 mint Gum and its immediate allies produce one group of 

 extracts which differ from the extracts of any other Euca- 

 lypt, so that it would be quite possible to identify such a 

 Gum by analysing its oils. But though the product of a 

 plant is constant in character, sometimes a peculiar oil 

 crops up in plants of many different families. The extract 

 that gives us the scent of citron is not only produced by 

 Citron, but by the Boronia we have referred to, by a 

 member of the Foxglove family, a Eucalypt, a Thyme, and 

 a Grass. These oils appear to be useless by-products 

 formed by the plant in the process . of nutrition and 

 growth, and as the plant has no means of throwing them 

 off, it stores them up in cells so as to get them away from 

 its actively -living parts. This would mean such a plant 

 has not the power of making the best use of its food. Such 

 an assertion sounds like rank heresy to those who see a 

 beautifully accurate adaptation in everything. Many 

 explanations have been brought forward to prove these 

 by-products are of great use to the plant. It is sometimes 

 claimed they render them distasteful to animals. Cer- 

 tainly, in some cases, they afford a partial protection, but 

 often, when we desire to gather a sprig of a Eucalypt for 

 our collection, we find not a single twig on the tree whose 

 leaves are not more or less. spoilt in shape by pieces that 

 have been eaten out by insects. If browsing animals spare 

 some of our Boronias, it is only because they are too small 

 to claim their attention. It ha* been suggested that the 

 oils evaporating from a modified atmosphere surround and 

 protect the plant from the injurious effect of intense light. 

 It is probable no one properly acquainted with Australian 

 conditions will waste time in attempting to refute this. 



