Cushman — Post-Mortem Detection of Strychnine. 543 
The qualitative examination of the weighed residue as has 
already been pointed out is divided into three groups, chemi- 
cal, morphological and physiological. A minute portion of 
the residue is dissolved in a drop of strong sulphuric acid 
and touched with a moist crystal of potassium dichromate the 
beautiful purple oxidation product changing rapidly through 
crimson to cherry red immediately appears. A minute por- 
tion of the residue is dissolved in a drop of strong sulphuric 
acid on platinum foil. If the foil is now connected with the 
positive pole of a dry cell battery and the drop of acid touched 
with a platinum wire from the negative pole immediately the 
blue oxidation tint will flash out. 
A portion of the residue dissolved in dilute acetic acid, the 
acid evaporated off, this residue taken up with water and ex- 
posed to the fumes of ammonia, gives beautiful tufts and silky 
needle-like crystals of the alkaloid, which can be studied with 
the microscope. A little of the residue dissolved ina drop of 
nitric acid gently warmed and touched with a minute particle 
of potassium chlorate produces an intense scarlet coloration. 
If to a dilute acetic acid solution of a portion of the 
residue a drop of potassium chromate solution is added, 
beautiful characteristic bush-like crystals and octahaedra of 
the chromate are formed and can be observed under the 
microscope. These crystals touched with sulphuric acid give 
the oxidation test. 
Potassium ferro-cyanide and picric acid also give highly 
characteristic miscroscopic crystalline forms. 
A very small portion dissolved in a dilute acid and further 
diluted with water has a persistent and distinct bitter taste 
when a drop of the solution is placed upon the back of the 
tongue. One part of strychnine in 700,000 parts of water can 
be detected in this way. | 
As a final test the physiological effect on a frog is tried ; 2.1 
mg. per kilogram weight is the minimum fatal dose for a 
frog. For an average sized frog weighing 50 grams this 
means the astonishingly small amount of 0.05 mg. In our 
cases 1. mg. was dissolved in a drop of acetic acid, about fif- 
teen drops of water added, and something less than one-tenth 
