  This work considers the idea of massive black holes being the constituents of
the Galactic dark matter halo. It constrains the maximum black hole mass to
$\mbh \sil 5 \times 10^4 \msun$ by examining their influence on the population
of globular clusters in our Milky Way. In the adopted halo model, globular
clusters are exposed to constant bombardment of halo objects on their orbits
through the Galaxy and thus will steadily gain internal energy. Depending on
the mass of these halo objects and the structural parameters of the globular
clusters, they can be disrupted on time scales of a few billion years and
below. These disruption time scales are calculated using a modification of the
well known (classical) impulsive approximation and compared with direct N-body
simulations of such encounter events to ensure the method works correctly. For
a set of ten prototypical globular cluster models and black hole masses ranging
from $10^3$ to $10^7\:\msun$, Monte-Carlo-simulations of $10\,000$ encounter
histories over the period of 10 billion years were calculated each, at three
different galactocentric distances \mbox{$R = 5$}, $10$ and $15\, \kpc$. These
data were compared with the real globular cluster population in our Galaxy and
used to obtain the above constraint of $\mbh \sil 5 \times 10^4 \msun$.
