ALKALOIDS. 617 



Analytical reactions : 



1. Five milligrammes of physostigmiue dissolved in 2c.c. of 

 ammonia water yield a yellowish -red liquid which, on evaporation 

 on a water-bath, leaves a blue or bluish -gray residue, soluble in 

 alcohol, forming a blue solution. Upon supersaturation with acetic 

 acid this becomes violet and exhibits a strong reddish fluorescence. 

 The violet solution leaves on evaporation a residue which is first 

 green and afterward blue. (Plate VI., 7.) 



2. Physostigmine or its salts give with calcium oxide and water a 

 red liquid which turns green on heating. 



Aconitine, Aconitina, C 34 H 47 NO n . Found in various species of 

 aconitum to the amount of about 0.2 per cent. It is a white crystal- 

 line powder, requiring for solution 3200 parts of water or 22 parts 

 of alcohol. 



Aconitine is one of the most poisonous substances known and 

 should never be tasted except in highly diluted solutions, which cause 

 a characteristic tingling sensation when brought in contact with the 

 mucous surfaces of the tongue. A dilute aqueous solution is precipi- 

 tated by alkalies, tannic acid, mercuric potassium iodide, but only 

 concentrated solutions yield precipitates with platinic chloride, mer- 

 curic chloride, and picric acid. 



Any soluble salt of aconitine in dilutions of 1 : 1000 produces 

 with a drop of potassium permanganate solution a blood-red precipi- 

 tate of aconitine permanganate. 



Colchicine, Colchicina, C^H^NOg = 396.23. This alkaloid is 

 obtained from Colchicum. It is a pale yellow amorphous powder or 

 leaflets, having a very bitter taste. It is soluble in 22 parts of water 

 and very soluble in alcohol and chloroform. It melts at 142 C. 

 (288 F.). Sulphuric acid produces a citron-yellow color, changed 

 to greenish-blue, then to red, and finally to yellow by the further 

 addition of nitric acid. Excess of potassium hydrate changes this 

 to red. 



Ptomaines (Putrefactive or cadaveric alkaloids). It has been 

 known for a long time that vegetable, and more especially animal 

 matter, when in a state of decomposition (putrefaction) acts generally 

 as a poison, both when taken as food or when injected under the skin. 

 Though many attempts had been made to isolate the poisonous pro- 

 ducts, this was not accomplished successfully until the years 1873 to 



