In the Pearl, chapter 1, Juana's first born child gets stung by a scorpion. It's fatal to the baby and they're in need of urgent care. But they cannot afford treatment.
Pearl chapter 1 & 2 summary
In chapter 2, Kino and Juana go to the ocean in a canoe in hope of finding a pearl. Kino ends up finding the 'Pear of the World.' Then they suddenly realize the possibilities they have now.
Side note: In chapter 1, the doctor denied treatment to their baby (Coyotito) because they didn't have enough money, and because he didn't want to treat 'low indians.'
Kino and Juana get married, and the doctor comes by to treat their babys' wound. Knowing they have a fairly large pearl on them. Later that night, a robber comes into Kino and Juana's house to steal the pearl, but Kino defends himself and fights them off.
Juana claims the pearl is a great evil, and wants to destroy it. But Kino insists they sell it, so they're son can have an education, new clothes, etc.