Sylvia was sick throughout the time she was pregnant with Alden. She consulted a doctor after the baby was born, and the doctor diagnosed her with neurasthenia.
Nowadays, if someone mentions having neurasthenia, we usually assume s/he is a hypochondriac. Even then, some people were dubious about the disease. However, medical historians say some diagnoses of neurasthenia in the 1910s legitimately described physical ailments that have been reclassified with new names today.
The diagnosis threw Sylvia under suspicion. Mission officials believed the diagnosis was contrived so that the family could go home without fulfilling their contract as teachers. The Caldwells were accused of secretly saving money so they could go home on their own if the mission wouldn't pay for their trip.
Remember that $100 in gold? It was indeed secretly saved from their salary. Today it would be worth about $2,200 -- not nearly enough to go home on, but it was certainly a substantial savings.
The mission reluctantly OKed them to go home, but the head of the mission wrote to his bosses in New York, "Have one or more of the Board's Drs. examine Mrs. Caldwell in America before settling their account." If Sylvia were found to be healthy, the couple would have to pay back their extremely expensive journey home.
Above are, from left, Albert Caldwell, Sam Conybeare, Sylvia Caldwell, and Bess Conybeare. The Conybeares were great friends of the Caldwells and were fellow missionaries in Siam. (Photo courtesy of Anne Conybeare Trach and Marcia Trach. Photo is copyrighted.)