“If the brucine is only one-tenth of the mixture, the blue-violet colour is obtained. A large excess of atropine does not prevent or obscure the strychnine reaction. A solution of 1 milligrm. atropine sulphate evaporated to dryness, together with 5 c.c. of a solution of strychnine (1 : 100,000) has no influence on the reaction, neither in the proportion of 1 mgrm. to 1 c.c. of the same solution; neither has cinchonine nor quinine any effect.
“Morphine obscures the reaction in the following proportions:—
“A solution of 0·01 mgrm. strychnine evaporated with a solution of 1 mgrm. of morphine sulphate on a water-bath, yields a blurred strychnine reaction when the residue is dissolved in sulphuric acid, and a crystal of potassic permanganate added. But still there is evidence whereby to suspect the presence of strychnine.
“A solution of 2 mgrms. of morphine sulphate treated in like manner with 0·01 mgrm. of strychnine yields like results.
“A solution of 3 mgrms. of morphine sulphate evaporated to dryness, with a solution of 0·01 mgrm. strychnine yielded results with the potassic permanganate test the same as if no strychnine was present.
“A solution of 1 mgrm. of morphine sulphate, treated as above, with a solution of 0·1 mgrm. strychnine, offered positive proof of the presence of the latter.”[448]
[448] Flückiger’s Reactions, translated by Nagelvoort, Detroit, 1893.
Dragendorff was able to render evident ·025 mgrm. mixed with twenty times its weight of quin. sulphate; the same observer likewise recognised ·04 mgrm. of strychnine in thirty-three times its weight of caffeine. Veratrine is likewise not injurious.