He began by examining the little dark cylinder on the end of the reed. On a piece of the stuff, broken off, he poured a dark liquid from a brown-glass bottle. Then he placed it under a microscope.
“Microscopically,” he said slowly, “it consists almost wholly of minute, clear granules which give a blue reaction with iodine. They are starch. Mixed with them are some larger starch granules, a few plant cells, fibrous matter, and other foreign particles. And then, there is the substance that gives that acrid, numbing taste.” He appeared to be vacantly studying the floor.
“What do you think it is?” I asked, unable to restrain myself.
“Aconite,” he answered slowly, “of which the active principle is the deadly poisonous alkaloid, aconitin.”
He walked over and pulled down a well-thumbed standard work on toxicology, turned the pages, then began to read aloud:
Pure aconitin is probably the most actively poisonous substance with which we are acquainted and, if administered hypodermically, the alkaloid is even more powerfully poisonous than when taken by the mouth.
As in the case of most of the poisonous alkaloids, aconitin does not produce any decidedly characteristic post-mortem appearances. There is no way to distinguish it from other alkaloids, in fact, no reliable chemical test. The physiological effects before death are all that can be relied on.
Owing to its exceeding toxic nature, the smallness of the dose required to produce death, and the lack of tests for recognition, aconitin possesses rather more interest in legal medicine than most other poisons.
It is one of the few substances which, in the present state of toxicology, might be criminally administered and leave no positive evidence of the crime. If a small but fatal dose of the poison were to be given, especially if it were administered hypodermically, the chances of its detection in the body after death would be practically none.