CRIMINAL MISCHIEF 32: Toxicology Part 1

From HOWDUNNIT: FORENSICS

https://www.dplylemd.com/books/forensicscience

WHAT IS A POISON? 

The terms poison, toxin, and drug are simply different ways of saying the same thing. Though you might think that a poison kills, a toxin harms, and a drug cures, these terms can be used almost interchangeably. The reason is that what can cure can also harm, and what can harm can kill. 

Anything and everything can be a poison. The basic definition of a poison is any substance that, if taken in sufficient quantities, causes a harmful or deadly reaction. The key here is the phrase “sufficient quantities.” 

The toxicity of any substance depends on how much enters the body and over what time period it does so. For example, you probably know that arsenic is a poison, but did you know that you likely have arsenic in your body right now? If you’re a smoker, you have more than a little bit. Same with mercury and cyanide. These substances are in the environment—you can’t avoid them. But they are in such small quantities that they cause no real harm. However, take enough of any of them and they become deadly.

The same can be said for the medications your doctor gives you to treat medical problems. Consider the heart drug digitalis, which comes from the foxglove plant and has been used for over a hundred years to treat heart failure and many types of abnormal heart rhythms. It is also a deadly poison. Too much can lead to nausea, vomiting, and death from dangerous changes in the rhythm of the heart. It’s ironic that it can treat some abnormal heart rhythms while at the same time can cause other more deadly rhythms. It’s all in the dosage. The right dose is medication; the wrong dose is poison. 

TOXICOLOGICAL TESTING

Toxicology is a marriage of chemistry and physiology, since it deals with chemical substances (chemistry) and how these substances alter or harm living organisms (physiology), particularly humans. 

A forensic toxicologist deals with the legal aspects of toxicology. His job is to find and analyze toxic substances in biological materials taken from both the living and the dead, and to determine the physiological, psychological, and behavioral effects on the individual in question. For example, he might be asked to assess the state of inebriation of an automobile accident victim or to determine if someone died from a poison or if the presence of a drug contributed to the victim’s death. This is often more difficult than it sounds. 

When the toxicologist investigates a possible poisoning death, he must answer three basic questions: 

Was the death due to a poison?

What was the poison used?

Was the intake of the poison accidental, suicidal, or homicidal?