Complex sentence: With so many possible symptoms, hysteria was always a catchall diagnosis where any unidentifiable ailment could be assigned, and so, as diagnostic techniques improved, the number of cases were pared down until nothing was left.
Split into simpler sentences: With so many possible symptoms, hysteria was always considered a catchall diagnosis where any unidentifiable ailment could be assigned. As diagnostic techniques improved, the number of cases were pared down until nothing was left.