Complex sentence: She was not well when she left Chicago, and she contracted a severe cold, which through the pressure of her work developed into typhoid pneumonia, of which she died December 12,1891, in Boston, and was buried at Riverview Cemetery, in Streator.
Split into simpler sentences: She was not well when she left Chicago, and she contracted a severe cold, which through the pressure of her work developed into typhoid pneumonia, of which she died December 12,1891. She died 12 December 1891 in Boston, and was buried at Riverview Cemetery, in Streator.