Strychnine is soluble with difficulty in water, its salts much more easily so. It is one of the most intensely bitter of the alkaloids  It gives reactions in very dilute solutions with most of the general alkaloidal reagents. The chlorides of gold and platinum do not react in very dilute solutions, perhaps, below 0.1 per cent. to 0.01 per cent.

S1. Strychnine forms a colorless solution with concentrated sulfuric acid.  I

S2. To the dry substance add a drop of concentrated acid, about one part water to five parts of acid, then by means of a glass rod, draw through the solution a minute crystal of potassium dichromate. A series of colors results, always in the same order:  first blue which quickly becomes violet, then more slowly red, pink, and yellow. The colors are characteristic of strychnine and, when the substance is pure will be produced by as small an amount as fifty-thousandth of a grain. The reaction is, however, interfered with by the presence of a number of organic compounds, including morphine.

S3. Vanadium sulfate in concentrated sulfuric acid  dissolves the solid compounds with the production, first of a blue, followed by a violet and red color. If it is then diluted  with water the pink remains for a long time.

S4. Cerium oxide with strychnine in concentrated sulfuric  acid gives the same color as the last reagent. It is said to react with one millionth of a gram. To make the reagent, heat cerium oxalate to redness to form the oxide and dissolve  this in thirty times its weight of concentrated sulfuric acid.

S5. Strychnine gives no color when treated with concen-trated sulfuric acid and a molybdate, nitrate, or nitric acid.

S6. Concentrated nitric acid colors strychnine or its salts  only faintly yellow, if at all, when it dissolves them, but on standing the solution becomes a darker yellow (difference  from brucine).