  We analyze the rotation curves of 10 spiral galaxies with a newtonian
potential corrected with an extra logarithmic term, using a disc modelization
for the spiral galaxies. There is a new constant associated with the extra term
in the potential. The rotation curve of the chosen sample of spiral galaxies is
well reproduced for a given range of the new constant. It is argued that this
correction can have its origin from string configurations. The compatibility of
this correction with local physics is discussed.
