84 PHARMACEUTICAL BOTANY 



taining seeds, previously treated with petroleum ether and absolute 

 alcohol, are mounted in a solution of i Gm. ammonium vanadate 

 in 100 mils of sulphuric acid, they take on a violet-red color which 

 later changes to brown. 



Veratrine. This alkaloid, with a composition of CarE^NOn, 

 is found in various parenchyma cells of Veratrum album. If sections 

 of the rhizome or roots are mounted in 2 drops of water and a drop 

 of concentrated H 2 SO 4 and examined microscopically on a glass 

 slide, the cell contents and walls of the cells which contain this sub- 

 stance first take a yellow color which soon changes to an orange-red 

 and then to a violet. 



Nicotine. This is a volatile alkaloid having the formula of 

 CioHi 4 N 2 which is found in the Nicotiana genus of the Nightshade 

 family* Sections of tobacco leaves or stems mounted in dilute 

 Lugol's solution will show first a carmine-red color and then a red- 

 dish-brown precipitate which in time loses its color. 



Caffeine. This alkaloid, with a formula of C 8 Hi N 4 O2 + H 2 O, 

 occurs in Thea, Cojfea, Cola, Sterculea, Ilex and Neea. If thin sec- 

 tions containing it are placed on a glass slide in 2 or 3 drops of con- 

 centrated hydrochloric acid and gently heated and then 2 or 3 drops 

 of gold chloride solution are added, the sections then pushed to the 

 side and the liquid allowed to evaporate, slender yellowish branch- 

 ing needles of caffeine gold chloride will be seen to separate. 



Cocaine. This narcotic alkaloid, having the formula Ci7H 2 iNO 4 , 

 is found in the leaves of Erythroxylon Coca and E. Truxillense. If 

 sections of these leaves are prepared in the same manner as indicated 

 for those containing Caffeine, but platinum chloride solution substi- 

 tuted for that of gold chloride, large feathers or plumes of cocaine- 

 chloro-platinate will be seen separating. 



Aconitine (C 3 3H 43 NOi 2 ) is found in various parts of Aconilum 

 Napellus. It is particularly abundant in the tuberous root of this 

 plant. If sections of aconite root are treated on a glass slide with 

 solution of potassium permanganate, a red precipitate of aconitine 

 permanganate will appear in the cells containing this alkaloid. 



Colchicine (C 22 H 2 5NO 6 ). This alkaloid occurs in the corm and 

 seeds of Colchicum aulumnale. It is very abundant in the cells 

 surrounding the fibro-vascular bundles of the corm. If a section of 



