INFLUENCE ON THE HUMAN SYSTEM. 77 



the reader that I am now smoking — as I have 

 been throughout these pages incessantly — and 

 will decidedly do so to the end — with rational 

 satisfaction : — 



" When the leaves of tobacco are mixed with water, 

 and submitted to distillation, a volatile oil or fat comes 

 over in small quantity. This fatty substance congeals, 

 or becomes solid, and floats on the surface of the water 

 which distils over along with it. It has the odour of tobacco, 

 and possesses a bitter taste. On the mouth and throat it 

 produces a sensation similar to that caused by tobacco- 

 smoke. When applied to the nose it occasions sneezing ; 

 and when taken internally it gives rise to giddiness, 

 nausea, and an inclination to vomit. It is evidently one 

 of the ingredients, therefore, to which the usual effects of 

 tobacco are owing ; and yet it is remarkable that from a 

 pound of leaves only two grains of this fatty body are ob- 

 tained by distillation. "Upon such minute quantities of 

 chemical ingredients do the peculiar action and sensible 

 properties of some of our most powerful medicinal agents 

 depend ! 



" When tobacco-leaves are infused in water made 

 slightly sour by sulphuric acid, and the infusion is sub- 

 sequently distilled with quicklime, there comes over, 

 mixed with the water, a small quantity of a volatile, oily, 

 colourless, alkaline liquid, which is heavier than Avater, and 

 to which the name of mcottn has been given. It has the 

 odour of tobacco, an acrid, burning, long-continuing tobacco 

 taste, and possesses narcotic and very poisonous qualities. 

 In this latter respect it is scarcely inferior to prussic acid, 

 a single drop being sufficient to kill a dog. Its vapour is 

 so irritating that it is difficult to breathe in a room in 



