  In this paper, we develop the theory of flashes of an algebraic curve. We
show that the theory is birationally invariant in a sense which we will make
more precise below. We also show how the theory provides a foundation for the
method of asymptotic degenerations, a particular class of degenerations of
plane projective algebraic curves. In particular, we consider the geometrical
technique in relation to the Severi problem of degenerating nodal curves to
lines in general position, and correct Severi's original proof of his
conjecture.
