394 British Association for the Advancement of Science. 



boiling point. Under such varied circumstances, the fluid procured, 

 on being rectified by a second distillation, is an aqueous solution of 

 nicotin, having the following properties. It is colourless and trans- 

 parent. Its odour closely resembles that of tobacco, but is far more 

 pungent. Its taste is peculiar, and leaves a sharp biting impression 

 on the tongue for some time. It changes turmeric paper to brown ; 

 but this effect is not permanent, but gradually disappears on expo- 

 sure to the air. Its specific gravity (according to repeated trials 

 made by two intelligent pupils of the author, Mr. Richard Austin 

 and Mr. John Keogh, who assisted him in many of his experiments,) 

 is about that of distilled water. It neutralizes the mineral and ve- 

 getable acids, forming peculiar salts, some of which the author has 

 obtained in a crystallized, and others in an imperfectly crystallized 

 state. It undergoes no apparent change by being kept in close 

 vessels for a considerable length of time. It is volatile below the 

 point of boiling water. It precipitates the greater number of metals 

 from their solutions, as those of silver, mercury, tin, antimony, man- 

 ganese, of a white colour ; iron of a green, cobalt of a pink, and 

 gold and platina of a yellow colour. 



Salts of Nicotin. — A number of the salts of nicotin, as the nitrate, 

 sulphate, &c, crystallize in four- and six-sided prisms ; they are cha- 

 racterized by having a sharp biting taste, analogous to that of aqueous 

 nicotin : they are mostly soluble in water, and are easily decomposed 

 by a slight increase of temperature. The nitrate is so susceptible 

 of change, that it seems to undergo an incipient decomposition when 

 exposed in solution for a few hours, and assumes a reddish colour. 

 The author's experiments have led him to conclude that nicotin is 

 composed of carbon, hydrogen, oxygen, and nitrogen, but he is 

 not yet satisfied as to its exact constitution. He made some ex- 

 periments to try the effects of aqueous nicotin on small fishes, flies, 

 moths, spiders, &c. A few drops of it diffused in a tumbler of wa- 

 ter strongly acted on the nervous system of small fishes, imme- 

 diately communicating to them an unusual but momentary energy, 

 which was speedily followed by torpor. 



Butterflies, moths, spiders, were soon killed by being brought in 

 contact with a weak solution of nicotin. Common flies resisted its 

 action better than spiders, drones, bees, or wasps, and after immer- 

 sion for a short time, again recovered on being exposed to the air for 

 a few minutes. Common caterpillars of a large size, on being taken 

 from cabbages, and instantly put into a weak solution of nicotin, ex- 

 hibited some energy, but presently became insensible, and being 

 considered as dead were suffered to remain in the solution for about 

 half an hour ; they were then removed to fresh water, but exhibited 

 not the slightest symptoms of life, but on being placed on a grass 

 plot near the house they all recovered, and were very active in the 

 course of an hour. 



The author is of opinion that aqueous nicotin may admit of a 

 number of useful applications, as in preparing specimens of natural 

 history for the museum, in preventing the destructive effects of the 

 insect tribes which infest plants and trees in gardens, conservatories, 



