PRODUCTION AND COMMERCE, 185 



vestigations. We may state that so far as we have been 

 able to ascertain no previous researches have been under- 

 taken on the subject. 



" Preliminary Examination. — The presence of an alka- 

 loid was demonstrated on the addition of the usual 

 reagents to the acid infusion. 



" Isolation of Alkaloid for Physical Examination. — The 

 powdered tumbeki was placed in a retort with milk of 

 lime and steam passed through it till the distillate was 

 no longer alkaline. Alkaloid in abundance was found in 

 the distillate, which had a distinct odour of nicotine. 

 The distillate was then extracted with ether, and the 

 ether slowly driven off. The residue obtained was a 

 light straw coloured oily liquid of powerful odour, giving 

 off irritating fumes when heated. 



" Estimation of Nicotine. — In the estimation of nicotine 

 much difficulty was experienced, owing to imperfect 

 knowledge of the alkaloid, and to the imperfect methods 

 recommended in various papers on the subject. The only 

 method we found reliable was by using a standard solu- 

 tion of Mayer's reagent, obtained by mixing 13-54:6 

 grams of mercuric chloride in solution with 49 • 8 grams 

 of potassic iodide, in solution, and adding water to make 

 1 litre.* One c.c. of this solution represents "003945 

 grams of nicotine, the precipitate having the formula 



CioHieNJ,.HgI,. 



" The method we adopted of working with this solution 

 was as follows : — One or more grams of dried and 

 powdered tumbeki were treated with diluted sulphuric 



* Dragendorff, 'Chemische Werthbestimmung starkwirkender 

 Droguen,' § 63, p. 52 et seq. 



