Gottlieb finally finds employment with Hunziker Pharmaceutical Company, of Pittsburgh, an institution that he has always criticized for doubtful vaccines and money-making addiction. Since he is to be given free range in the laboratory, however, he accepts with joy. Dr. Rouncefield, in his Chicago clinic, chuckles over the change in one whom he considers a "super-highbrow." In Wheatsylvania, North Dakota, young Dr. Arrowsmith protests to Leora that he never believed Gottlieb would fall for "those crooks." Leora insists that there must be a good reason for it. Gottlieb and his family immediately move to Pittsburgh and five thousand a year.
The first six months in Pittsburgh proceed well. Not until then does Gottlieb realize that his young technical experts resent his thrusts at commercialism. He also discovers that Hunziker Company is producing and selling unethical products on the side, such as a "cancer remedy" with the value of mud and a complexion cream guaranteed to turn dark skin white.
At this time, Gottlieb makes a discovery that is the culmination of twenty years of test tube research. Immediately Dawson Hunziker tries to force the scientist to produce the antitoxin in large quantities and to market it at once. Gottlieb, wishing for further proof of the serum's efficacy, delays production, to the irritation of Hunziker. In the meantime, Mrs. Gottlieb dies; Robert, the son, develops extravagant and dishonest character traits; and the older daughter elopes with a gambler. Gottlieb sits alone, reading the book of Job.
Miriam, however, rises to the occasion. She discontinues her music lessons and takes over the household. Then Gottlieb receives an offer to become chief of the Department of Bacteriology and Immunology of McGurk Institute of Biology, in New York, at a salary of ten thousand a year. This old and reputable firm is on a sound ethical as well as financial basis, with Dr. A. DeWitt Tubbs as director.
Throughout his employment by Hunziker, Gottlieb remains steadfast in his convictions, refusing to compromise even for the sake of fame and money. His new position with McGurk is more in keeping with the character of the man. He suffers the afflictions of Job in his family life, but he is never resentful and never gives up his ideals of pure science.
Chapters XII and XIII bring the Gottlieb story up to the time of Arrowsmith's becoming established in Wheatsylvania. There is some parallelism between the careers of the old scientist and the young during this period, both being forced by circumstance into avenues not in line with their more specialized abilities.