Antibiotics
Year of Discovery: 1910
What Is It? Chemical substances that kill infectious microscopic organisms
without harming the human host.
Who Discovered It? Paul Ehrlich
Why Is This One of the 100 Greatest?
The word “antibiotic” comes from the Greek words meaning “against life.” Early folk
medicine relied on some natural compounds that cured certain diseases—the ground bark of
a tree, certain cheese molds, certain fungi. Doctors knew that these natural compounds
worked, but had no idea of how or why they worked.
Paul Ehrlich conducted the first modern chemical investigation of antibiotics and discovered the first antibiotic chemical compounds. His work opened a new era for medical
and pharmacological research and founded the field of chemotherapy. Antibiotics (penicillin, discovered in 1928, is the most famous) have saved many millions of lives and trace
their modern origin to Paul Ehrlich’s work.
How Was It Discovered?
Paul Ehrlich was born in Germany in 1854. A gifted student, he entered graduate
school to study for a medical degree. There he became deeply involved in the process of
staining microscopic tissue samples so that they would show up better under the microscope. The problem was that most dyes destroyed the tissue samples before they could be
viewed. Ehrlich struggled to find new dyes that wouldn’t harm or kill delicate microscopic
organisms. This work showed Ehrlich that some chemical compounds killed some types of
tissue and made him wonder if the process could be controlled.
By 1885 it had become clear that the causative agent for many illnesses was microorganisms. Many scientists made a great effort to study these bacteria under the microscope.
Again Ehrlich found that many of the available dyes and stains killed the organisms before
they could be studied. This finding inspired Ehrlich to propose that chemical compounds
may exist that could kill these organisms without harming the human patient, thus curing an
illness by killing only its causative agent.
In the mid-1890s, Ehrlich shifted his focus to studies of the immune system and how to
control the reaction between chemical toxins and antitoxins. Again it occurred to Ehrlich
that, just as antitoxins specifically sought a toxin molecule to which they were related and
destroyed it, so, too, he might be able to create a chemical substance that would go straight
124