Pasteur was absolutely done up, but Roux--and he was helped by the intrepid Yersin who afterward brilliantly discovered the germ of the black death--set out to try to find a way to wipe diphtheria from the earth. It wasn’t a science--it was a crusade, this business. It was full of passion, of purpose; it lacked skillful lying-in-wait, and those long planned artistic ambushes you find in most discoveries. I will not say Émile Roux began his searching because of this pitiful note from that woman--but there is no doubt he worked to save rather than to know. From the old palsied master down to the most obscure bottle wiper, the men of this house in the Rue Dutot were humanitarians; they were saviors--and that is noble!--but this drove them sometimes into strange byways far off the road where you find truth.... And in spite of this Roux made a marvelous discovery. Roux and Yersin went to the Hospital for Sick Children--diphtheria was playing hell with Paris--and here they ran on to the same bacillus Loeffler had found. They grew this microbe in flasks of broth, and did the regular accepted thing first, shooting great quantities of this soup into an assorted menagerie of unfortunate birds and quadrupeds who had to die without the satisfaction of knowing they were martyrs. It wasn’t particularly enlightened searching, this, but almost from the tap of the gong, they stumbled on one of the proofs Loeffler had failed to find. Their diphtheria soup paralyzed rabbits! The stuff went into their veins; in a few days the delighted experimenters watched these beasts drag their hind legs limply after them; the palsy crept up their bodies to their front legs and shoulders--they died in a clammy, dreadful paralysis.... “It hits rabbits just the way it does children,” muttered Roux, full of a will to believe----“This bacillus must be the true cause of diphtheria.... I shall find the germ in these rabbits’ bodies now!” And he clawed tissues out of a dozen corners of their carcasses; he made cultivations of their spleens and hearts--but never a bacillus! Only a few days before he had pumped a billion or so into them, each of them. Here they were, drawn and quartered, carved up and searched from their pink noses to the white under-side of their tails. And not a bacillus. What had killed them then? Then Loeffler’s prediction flashed over Roux: “It must be the germs make a poison, in this broth, to paralyze and kill these beasts ...” he pondered.