PEODUCTION AND COMMERCE. 187 



salts contained in the leaves. Dr. Kissling * has also 

 noticed the high percentages obtained by this method of 

 estimating nicotine. 



" Kosutany treats the leaves with milk of lime till all 

 the ammonia is driven off, and then extracts with water ; 

 shakes the aqueous solution with petroleum ether and 

 proceeds as before. 



" This method was not found to give good results, 

 for though the ammonium salts do not interfere with 

 the reaction, yet the petroleum ether does not extract 

 the whole of the alkaloid, and thus a low percentage is 

 obtained. 



" Extraction by Ammoniacal Ether. This consists in 

 extracting the powdered leaves in an upright extractor, by 

 an ethereal solution of ammonia, and either driving off the 

 ether and weighing the residue as nicotine ; or volumetri- 

 cally estimating the residue by decinormal solution of 

 sulphuric acid, or precipitating the alkaloid by platinum 

 perchloride. In either case, whichever way the residue is 

 estimated, the results are too high, owing to the difficulty 

 of entirely getting rid of the ammonia. 



" The following are the percentages of nicotine in the 

 tumbeki : 



' Ispahan' I. By Mayer's Eeagent. 



A. (midrib) 8 -156 percent. 



B. (leaf)-. 5-508 * 



C. (leaf and midrib) 5 '589 



D. (leaf) 5-3865 



5-4945 per cent, average. 

 * The ' Analyst,' January 1886, p. 16 ; Chem. Zeit.,' ix., 1886. 



