  I investigate the process of converting gas into stars within the framework
of a standard cosmological model. By examining the set of objects grown in a
combined N-body plus smoothed particle hydrodynamics simulation with those
obtained in similar models where some of the cold, dense gas was replaced by
collisionless ``star'' particles I show that it is possible to make this
substitution without affecting the subsequent gas cooling rate. With even the
most basic star forming criteria the masses of isolated objects are nearly
identical to the mass of cold, dense gas found within the same objects in a
non-star forming run.
  No evidence is found to support the contention that converting gas into stars
might affect the amount of cold gas obtained in a simulation by retarding the
cooling rate within those objects where stars have already formed. In practice,
because cold gas can be reheated by shocks but stars remain as such whatever
happens the masses of the largest objects found in the star forming runs are
generally higher than those in the standard run.
  Finally, I demonstrate that an excellent match to the observed star formation
rate can be achieved with even a very basic star formation prescription.
