  Modified Newtonian Dynamics (MOND) is a possible solution for the missing
mass problem in galactic dynamics; its predictions are in good agreement with
observations in the limit of weak accelerations. However, MOND does not derive
from a physical mechanism and does not make predictions on the transitional
regime from Newtonian to modified dynamics; rather, empirical transition
functions have to be constructed from the boundary conditions and comparison to
observations. I compare the formalism of classical MOND to the scaling law
derived from a toy model of gravity based on virtual massive gravitons (the
"graviton picture") which I proposed recently. I conclude that MOND naturally
derives from the "graviton picture" at least for the case of non-relativistic,
highly symmetric dynamical systems. This suggests that - to first order - the
"graviton picture" indeed provides a valid candidate for the physical mechanism
behind MOND and gravity on galactic scales in general.
