Paul Ehrlich was ten years younger than Robert Koch; he was in Cohnheim’s laboratory on that day of Koch’s first demonstration of the anthrax microbe; he was atheistical, so he needed some human god and that god was Robert Koch. Painting a sick liver Ehrlich had seen the tubercle germ before ever Koch laid eyes on it. Ignorant, lacking Koch’s clear intelligence, he supposed those little colored rods were crystals. But when he sat that evening in the room in Berlin in March, 1882, and listened to Koch’s proof of the discovery of the cause of consumption, he saw the light: “It was the most gripping experience of my scientific life,” said Paul Ehrlich, long afterwards. So he went to Koch. He must hunt microbes too! He showed Robert Koch an ingenious way to stain that tubercle microbe--that trick is used, hardly changed, to this day. He would hunt microbes! And in the enthusiastic way he had he proceeded to get consumption germs all over himself: so he caught consumption and had to go to Egypt. II Ehrlich was thirty-four years old then, and if he had died in Egypt, he would certainly have been forgotten, or been spoken of as a color-loving, gay, visionary failure. He had the energy of a dynamo; he had believed you could treat sick people and hunt microbes at the same time; he had been head physician in a famous clinic in Berlin, but he was a very raw-nerved man and was fidgety under the cries of sufferers past helping and the deaths of patients who could not be cured. To cure them! Not by guess or by the bedside manner or by the laying on of hands or by waiting for Nature to do it--but how to _cure_ them! These thoughts made him a bad doctor, because doctors should be sympathetic but not desperate about ills over which they are powerless. Then, too, Paul Ehrlich was a disgusting doctor because his brain was in the grip of dreams: he looked at the bodies of his patients: he seemed to see through their skins: his eyes became super-microscopes that saw the quivering stuff of the cells of these bodies as nothing more than complicated chemical formulas. Why of course! Living human stuff was only a business of benzene rings and side-chains, just like his dyes! So Paul Ehrlich (caring nothing for the latest physiological theories) invented a weird old-fashioned life-chemistry of his own; so Paul Ehrlich was anything but a Great Healer; so he would have been a failure----But he didn’t die!