Suppose N is a closed
n-dimensional smooth manifold and M is a 2n-dimensional smooth manifold. In
1944, H. Whitney defined the self-intersection number for an immersion with normal
crossings f : N → M. We show that, if N is path-connected and the James-Thomas
number of the normal bundle ν(f) of f is greater than 1, then the self-intersection
number is completely determined by the homotopy class of f and the normal bundle
ν(f).