44 



lightest and most diffusible of all elements in nature, when in com- 

 bination with all other elements, except oxygen, produces the most 

 powerfully odorous bodies with which we are familiar. Modifying 

 influences in the production of smell are heat and cold, light, elec- 

 tricity, relative dryness and humidity of the atmosphere, friction, 

 striking, &c. The absorption and radiation of odours seem to be 

 regulated in the same way as in the case of light. Black absorbs 

 most, or rather radiates least. White radiates most. Hence 

 clergymen and doctors accustomed to visit infected houses should 

 not wear black. There seems to be some relation between the 

 colours of flowers and their odours. Blue is rarely combined with 

 scent. White flowers are generally fragrant. Orange, brown, and 

 lurid ones are generally disagreeable — probably from presence of 

 sulphur. 



The laws of intensity, diffiusibility, and permanence have not 

 been determined. Speaking about permanence, there is a wonderful 

 instance of this on record. Some fossil Teredos or borers were 

 found in some fossil drift wood in an excavation near Brussels, not 

 long ago. These little animals belonged to that geological epoch 

 which is called the Tertiary period. When fractured they emitted 

 a strong smell of seaweed ; thus preserving the odour of the Ter- 

 tiary sea during the lapse of countless ages. The attempted classi- 

 fication of odours has hitherto proved futile. Even chemistry 

 seems here at fault, as many odorous bodies are found in the labo- 

 ratory to be identical, which the more acute analysis of the olfactory 

 nerve resolves into different substances. Instances of this are the 

 oils of turpentine, bergamotte, lemon, cloves, parsley, &c. They 

 all consist of equal parts of carbon and hydrogen. The strongest 

 smelling bodies consist of these hydro-carbons, as they are called, 

 either combined with oxygen, nitrogen, sulphur, arsenic, or 

 phosphorus. For instance, a hydro-carbon called amyl, which is 

 found in brandy distilled from potatoes, when it is combined with 

 oxygen, furnishes potato ether. This, combined with spirits of 

 wine, acquires the peculiarly pleasant odour and flavour of Jar- 

 gonelle pears. This is used by confectioners to flavour their drops, 

 &c. The same ether, when combined with a nasty smelling sub- 



