206 THE HUMAN BODY. 



tend to prove that black garments are more quickly impreg- 

 nated with an odour, and retain it longer, than light-coloured 

 garments. On the other hand, A. Dumeril assures us he has 

 ascertained that white stuffs absorb odours as quickly as 

 others, but that the odoriferous particles are sooner evapor- 

 ated from them. There must consequently be in this respect 

 a difference in odours like that in luminous rays, but the first 

 of these phenomena has not been at all so clearly demon- 

 strated as the latter. 



Under the influence of a shock, or from friction, certain 

 vegetable and mineral bodies emit odours more or less power- 

 ful. Such are several varieties of wood, especially lilac and 

 Saint Lucy, the leaves of mint, lemon verbena, and southern- 

 wood, and certain calcareous or silicious rocks. Other plants, 

 on the contrary, lose their aroma on being bruised, like the 

 mignonette, the violet, &c. The contact of water, or of 

 vapour, also develops odours in argillaceous rocks and 

 several vegetable substances. 



Odours have a very marked effect on the nervous system; 

 but some persons are far more impressible in this respect 

 than others. There is no doubt that certain odours may 

 cause grave disturbance in the nervous system; but the ima- 

 gination sometimes plays a prominent part in the discomfort 

 produced by a bouquet of roses or violets; the sight of artifi- 

 cial flowers is sometimes sufficient to excite persons painfully 

 who believe them to be natural. People often ascribe to 

 this influence of odours on the brain, what is really due to the 

 effects of carbonic acid gas, or of poisonous emanations ab- 

 sorbed by the lungs; and how many persons there are who 

 do not believe the open combustion of charcoal is innocuous, 

 because it does not emit so much smell as coal. 



But even after making due allowance for the effects of the 

 imagination, it is certain that odours act as an excitant on 

 the brain, which may be dangerous when long continued. 

 They are especially dreaded by the Roman women. It is 

 well known that in ancient times the women of Rome in- 

 dulged in a most immoderate use of baths and perfumes; but 

 those of our times have nothing in common with them in this 

 respect; and the words of a lady are quoted, who said on 



