Many experiments have had a positive outcome; thousands of times as many have yielded nothing positive whatever. And for the subjects of the experiments, the animals destined to suffer, the service they were objectively rendering for science was a matter of indifference.

Perhaps we mean no more and no less to the higher power above us (I cannot believe in it and yet it is in my thoughts sometimes) than our cats and dogs, rats, guinea pigs, monkeys, horses–even bedbugs and lice do to us. I have experimented on bedbugs and lice, too. Science has long known that body lice transmit a very dangerous infectious disease, which, during wartime especially, has caused tremendous loss of life, namely, epidemic typhus, typhus exanthematicus. I believed I had found the pathogen of this disease in a certain bacillus. (Unfortunately this was not an error.) In 1917 I carried out experiments with body lice in the military epidemiology laboratory at the Russian-Polish front. This insect is so minute that the technical difficulties will be appreciated. What is the task? One must infect the insect with typhous blood, so that it becomes infectious. Is this clear? It is not easy. Nevertheless I was able to give the animal a stab with an exquisitely fine needle. But another researcher, a Pole, was even more resourceful. He was able to employ a very beautiful method to fill the gut of the millimeter-small insect with infectious material from behind. This procedure is not child’s play either, of course. It needs to be mastered in the same way as other bacteriological research methods. The result in any case is that a body louse fed with a certain pathogen becomes ill and dies. If its mortal remains are now smeared onto the skin of an ape and the ape licks the spot, it too becomes ill and dies quickly. And so it goes, first here, then there, from warm-blooded creature to cold-blooded creature. Lice, monkeys, lice, monkeys. It sounds grotesque, comical, but it is not.

At least momentarily, a positive result from a scientific experiment affords the investigator terrific satisfaction. I use the word “terrific” advisedly.

All the nightly vigils, all the diligent, exhaustive study, all the gnawing doubts and anxieties, all the time and expense, everything the investigator loses by giving up a social life, giving up reading, going to the theater and to concerts, above all by giving up a truly vigorous, conscious family life–it is all (for the moment) richly repaid by the feeling of knowledge gained, of having solved a puzzle, of having increased man’s power over things.

The renowned French physiologist Claude Bernard once called the scientific laboratory the “battlefield” of the experimenter. Certainly blood is shed. But there is a victory, too. And when he describes the task of the experimenter as to prévoir et diriger les phénomènes, who will dare to disparage the scientific investigator as a “cold mechanic of medicine”? No, he is much more like an experimenter-demigod probing the depths of the cosmos. And if he really is what he should be as an experimenter, he rises above the vulgar interests of men. He becomes a tragic figure. Or–and here the conflict begins–is he only a tragicomic figure? Was his “scientific result,” which in the best case is hauled for decades or a century through medical journals and scientific periodicals and books under his byline, really worth the trouble? Was it in many instances not even worth the electrical current that flowed through the lamps in his laboratory while he worked? Does it give meaning to meaninglessness? Does it take the horrifying out of the horror? Does it help? Can it be gratifying? Does the investigator’s interest not turn immediately to other problems, precisely like the hand of a cold mechanic? Is his thirst for happiness and inner peace ever appeased? Did the suffering of the sacrificed animals bring the investigator great things? If so, did it bring the nation great things too? Humanity? Did it transform the terrible disorder of nature into order and meaningful structure?

V

After the war I returned to my wife and immediately reopened the private surgical and gynecological clinic. But human disease could not hold me now. In my earlier zeal, I had made do with trained nurses. Now I brought in an assistant physician.

Success or failure, recovery with adverse effect or without it: I had seen the cheapness of an individual life too close at hand in combat and in military epidemic hospitals. Previously I had sacrificed animal lives on a vast scale in order to find something that might be of use in restoring even one human being to health.