Dubious toe claim 

I've added the dubious tag to the toe claim because:

 Given Cartwright's paternalistic attitude it seems implausible he would prescribe it.
 Szasz is not unbiased; besides, almost everyone is somewhat biased against racists.  Szasz is, anyway, not a primary source.
 It seems like all sources regarding drapetomania are actually secondary to one paper published by Cartwright.

My guess is that toes of runaway slaves were amputated, perhaps as "treatment" for drapetomania, but that Cartwright himself never prescribed this.  Anyway, perhaps I will check local libraries for the Szasz book, and try to find his source.  No promises though. –