PAPAVERINE. 
§§ 378. 379-1 
3i9 
a yellow colour ; on heating, red vapours are produced ; the fluid contains crystals of 
oxalic acid, and develops with potash a volatile base. Concentrated sulphuric acid 
colours pure narceine brown ; but if impure, a blood-red or blue colour may be pro¬ 
duced. It does not reduce iron salts. 
Frohde’s reagent colours it first brown-green, then red, passing into blue. Narceine 
forms precipitates with bichromate of potash, chloride of gold, bichloride of platinum, 
and several other reagents. The one formed by the addition of potassio-zinc iodide 
is in hair-like crystals, which after twenty-four hours become blue. 
Weak iodine solution colours narceine crystals a black-blue ; they dissolve in 
water at 100 ° without colour, but on cooling again separate with a violet or blue 
colour. If on a saturated solution of narceine a particle of iodine is strewn, fine 
needle-like grey crystals form around the iodine. A drop of “ Nessler ” solution, 
added to solid narceine, at once strikes a brown colour ; on diluting the drop with a 
little water, beautiful little bundles of crystals appear.— Fliickiyer. 
The following group reagents precipitate narceine :—Picric acid, tannin solution, 
and potassium dichromate on long standing. The following give no precipitate :— 
Mercuric cyanide, mercuric potass, iodide, mercuric chloride, mercuric bromide, and 
potass, ferrocyanide solutions. 
§ 378. Effects. —The physiological action of narceine has been variously inter¬ 
preted by different observers. Claude Bernard 1 thought it the most somnife ous of 
the opium alkaloids. He said that “ the narceine sleep was characterised by a pro¬ 
found calm and absence of the excitability of morphine, the animals narcotised by nar¬ 
ceine on awaking returning to their natural state without enfeeblement of the hind 
limbs or other sequelae.” It has been amply confirmed that narceine possesses somni¬ 
ferous properties, but certainly not to the extent that Bernard’s observations led 
physiologists to expect. In large doses there is some irritation of the stomach and 
intestines, and vomiting occurs, and even diarrhoea ; moderate doses induce con¬ 
stipation. The maximum medicinal dose may be put at -14 grm. (or 2-15 grains), 
and a probably dangerous dose would be three times that quantity . 2 
§ 379. Papaverine (C 20 H 21 NO 4 ) crystallises from alcohol in white needles or scales. 
It possesses scarcely any alkaline reaction, but its salts have an acid reaction ; it has 
but little effect on a ray of polarised fight. It is almost insoluble in water; it is 
easily soluble in acetone, amyl alcohol, alcohol, and chloroform. One part of the 
alkaloid is dissolved in 36-6 of benzene, in 76 parts of amyl alcohol, and in 490 parts 
of carbon tetrachloride. Petroleum ether dissolves it by the aid of heat, but the 
alkaloid separates in crystals on cooling. Chloroform extracts it from either acid or 
alkaline solutions. Papaverine gives no crystalline sublimate. The melting-point 
of pure samples in a tube is 147°, with scarcely any colour ; it solidifies again to 
crystals on cooling ; in the subliming cell it melts at 130°, and decomposes at about 
149° ; the vapours are alkaline ; the residue is amorphous, fight brown, and is not 
characteristic. Concentrated sulphuric acid colours it a deep violet-blue, and dis¬ 
solves it to a violet, slowly fading. This solution, by permanganate of potash, is 
first green and then grey. Some samples of commercial papaverine consist of ^-papa¬ 
verine, which dissolves in concentrated H 2 S0 4 to a colourless solution . 3 Frohdo’s 
reagent gives a beautiful violet colour, which becomes blue, and vanishes after twenty- 
four hours. Diluted solutions of salts of papaverine are not precipitated by phospho- 
molybdic acid. It is precipitated by ammonia, by the caustic and carbonated alkalies, 
by potassic-cadmic iodide, iodine in hydriodic acid, and by alkaloidal reagents generally 
—save by the important exception mentioned above. A solution in amyl alcohol is 
also precipitated by bromine ; the precipitate is crystalline. An alcoholic solution 
of platinic chloride also separates papaverine platinic chloride in crystals. An alcoholic 
1 Compt. Rend., fix. 406, 1864. 
2 See J. Bouchardat, La Narceine, These, Paris, 1865 ; Harley, The Old Vegetable 
Neurotics, Lond. ; Ch. Line, Etudes sur la Narceine et son emploi therapeutique, 
These, Paris, 1865 ; also, Husemann’s Pflanzenstoffe, in which these and other re¬ 
searches are summarised. 
3 Oswald Hesse, J. pr. Chem., 1903 (ii.). 
