Given the question: What's the profession of the person that Olga's sister is not in love with?  Answer the above question based on the context below:  After her sister Olga marries and leaves home, Katrin Koerber, the daughter of an Austrian medical professor, fights loneliness and dreams of a more exciting life outside Austria.  Consequently, when Dr. Walter Fane, a British bacteriologist, asks her to marry him and move to Hong Kong, she agrees, even though she is not in love with him. As soon as the newlyweds arrive in Hong Kong, however, Walter becomes consumed with his medical work, and Katrin becomes the romantic target of Jack Townsend, the unhappily married attaché to the British embassy.  While showing her the city's exotic sights, Jack flirts with Katrin and kisses her.  Katrin, unnerved by Jack's actions, retreats to her house, but soon rejoins him to observe local dancers performing at a Buddhist festival.  Stimulated by the dancing and the atmosphere of a Buddhist temple, Jack confesses his love to Katrin, and Katrin admits that she is not in love with Walter. At home, Katrin then treats Walter coolly and reveals that his chronic lateness and fatigue annoy her. To make amends, Walter comes home early the next day, but discovers Katrin's bedroom door locked and Jack's hat on a table.  That evening, Walter confronts Katrin with his suspicions, and she admits that she loves Jack.  Distraught, Walter tells Katrin that he will grant her a divorce only if Jack promises in writing that he will divorce his wife and marry her.  When Katrin presents Walter's conditions to Jack, he tells her that a divorce would ruin both his career and his reputation and backs out of the affair.
The answer is:
bacteriologist