The Elusive Magic Bullet Introduction

These strange ideas (at least in contemporary terms) should not, however, overshadow his major contribution to medicine, which was his forthright belief that each disease had a specific cause and its own remedy. There is an interesting congruence between this belief and the later triumphs of Paul 

Ehrlich, who invented just such a treatment for syphilis caused by the organism Treponema pallidum. 

He returned in 1889, completely recovered, and accepted an appointment at the Institute for Infectious Diseases in Berlin directed by Robert Koch. Ehrlich continued to develop his ideas about the specificity of chemicals for particular cells and for their structural components, but he also became heavily involved in the development of methods for the accurate measurement of the potency of diphtheria antitoxin. This seminal work is often overlooked 

The bacteriologist Emil von Behring had discovered specific antitoxins in the blood serum of animals infected with sub-lethal doses of diphtheria bacilli, but he was unable to produce samples with reproducible levels of activity. Ehrlich not only showed how to raise high concentrations of antitoxins in horses by successive injections of diphtheria bacilli but also developed the methods necessary for the measurement of the potency of the individual serum samples. The treatment of patients then became both safe and effective, and the fact that his methods are still in use today provides a cogent testimony to his skill and ingenuity. 

That they should have tried arsenic derivatives was not at all unreasonable, since these had been used not only by Paracelsus but also by many physicians 

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