  Andredakis, Peletier & Balcells (1995) fit Sersic's law $\mu(r) \sim r^{1/n}$
to the bulges of the Balcells & Peletier (1994) galaxy sample, and infer that
$n$ drops with morphological type T from $n \approx$ 4--6 for S0 to $n=1$
(exponential) for Sc's. We use collisionless N body simulations to test the
assumption that initially the surface brightness profiles of all bulges were
exponential, and that the steepening of the profiles toward the early-types is
due to satellite accretion. The results are positive. After the accretion of a
satellite, bulge-disk fits show that the bulge grows and that the bulge profile
index $n$ increases proportional to the satellite mass. For a satellite as
massive as the bulge, $n$ rises from 1 to 4. We present kinematic diagnostics
on the remnants and disk thickening. The latter suggests that the bulge growth
must have occurred before the last formation of a thin disk in the galaxy. The
thick disks created by the merger are reminiscent of thick disks seen in
early-type edge-on galaxies.
  The efficiency of the process suggests that present day bulges of late-type
spirals showing exponential profiles cannot have grown significantly by
collisionless mergers.
