Synthetic Men of Mars

Synthetic Men of Mars was published in 1940 and is one of the most unusual books in the Barsoom sequence. Dejah Thoris has been seriously injured. John Carter travels to the laboratory of Ras Thavas, the master mind from the earlier novel, hoping the great scientist can save her. Ras Thavas himself, however, has been forced into hiding inside Morbus, a city of synthetic humans called hormads that he originally created by mass-producing artificial bodies from vats.

The hormads have rebelled and seized power in Morbus, and one of them, the corrupted Number 1 Hormad, is now growing uncontrollably into a mass of undifferentiated tissue that threatens to engulf the entire region. Carter and his companion Vor Daj must work with Ras Thavas to put the synthetic men back under control before they destroy everything. The novel anticipates several later science-fiction themes about cloning, mass production of humans, and unchecked biological replication. Among the more imaginative late Barsoom books. Strange and worth reading.