I get the impression that the whole "graft hybrids" hypothesis
reflected vague, pre-modern-genetics notions of heritability, and
were supplanted by the "graft-chimera" explanation.

cheers

+ + +
Interesting. Apparently there are some effects by one component of a chimera
on the other, but they are not very major or they would be more prominent in
the public eye, to say nothing of the literature, grafting being as popular
as it is.
PvR

Note the discussion on xenotransplants.