In the early 20th century, the average American medicine cabinet was filled with radioactive radium, thallium, and morphine in everyday products. The scientific knowledge to detect and prevent crimes committed with these materials didn't evolve until 1918. New York City's first scientifically trained medical examiner, Charles Norris, and his chief toxicologist, Alexander Gettler, turned forensic chemistry into a formidable science and set the standards for the rest of the country.

[text adapted from PBS.org]