By the 1850s, people still didn’t know exactly what caused disease.
There were many theories, but none were based on scientific principles.
In 1858, the German physician Rudolf Virchow offered the first clue with his cell theory.
He said the cell, which Dutch inventor Antoni van Leeuwenhoek had seen 200 years earlier, was the basic unit of human life and that disease occurs when the function of cells is disrupted.
From this, he developed the science of pathology, the study of diseased body tissue.
Virchow applied his cell theory to both diseased and healthy tissue and asserted that diseased cells are produced by healthy cells.
For example, the first malignant cell in cancer is born from a healthy cell. It’s called a mutation, and it produces more cancerous cells.
Virchow proposed that a study of cells would explain what causes disease in the body.
Twenty-five years later, another German physician would use Virchow’s ideas to discover the chemistry behind disease and create a “magic bullet” to fight the process.
The biggest breakthrough in antibiotics came in 1928 when British bacteriologist Alexander Fleming discovered penicillin.
Penicillin is a non-poisonous chemical produced by mold that kills many different bacteria.