  The robustness of the factorization theorem for total cross sections,
$\sigma_{nn}/\sigma_{\gamma p}=\sigma_{\gamma p}/\sigma_{\gamma\gamma}$,
originally proved by Block and Kaidalov\cite{bk} for $nn$ (the even portion of
$pp$ and $\pbar p$ scattering), $\gamma p$ and $\gamma\gamma$ scattering, is
demonstrated. Factorization theorems for the nuclear slope parameter $B$ and
$\rho$, the ratio of the real to the imaginary portion of the forward
scattering amplitude, are derived under very general conditions, using
analyticity and the optical theorem.
