somatotropism

from The Collaborative International Dictionary of English v.0.48

Somatotropism \So`ma*tot"ro*pism\, n. [Gr. sw^ma, sw`matos, the
   body + tre`pein to turn.] (Physiol.)
   A directive influence exercised by a mass of matter upon
   growing organs. --Encyc. Brit.
   [1913 Webster] Somber