German microbiologist Adolf Mayer was one of the first scientists to study tobacco mosaic disease. Although he incorrectly concluded that it was caused by bacteria, other scientists would draw upon his work as they eventually discovered the disease's true cause--the tobacco mosaic virus (also known as TMV). TMV was the first virus ever identified.

Mayer attended college at the Universities of Heidelberg, Ghent, and Halle. In 1876, he moved to the Netherlands, where he became head of the Agricultural School at Wageningen. He was soon approached by a group of Dutch tobacco farmers whose crops were being ravaged by disease. They hoped Mayer could find a way to prevent the disease from spreading. (Tobacco had been brought to Europe from the New World, and by the middle of the 1800s, it was a major Dutch crop.)

Because it caused a mottled pattern to form on the plants' leaves, Mayer...