  We comment on the treatment of asymptotic black-disk scattering in a recent
paper of Nastase and Sonnenschein, Phys.\ Rev.\ D\ {\bf 92}, 015028 (2015), on
scattering in an updated version of the Heisenberg model which gives $pp$ and
$\bar{p}p$ cross sections which increase at very high energies as $\ln^2s$. We
show that the total cross section they define does not correspond to that
measured in experiments, with the result that their limit for the ratio
$\sigma_{\rm elas}/\sigma_{\rm tot}$ is too small by a factor 2. The correct
ratio for black-disk scattering, $\sigma_{\rm elas}/\sigma_{\rm tot}
\rightarrow 1/2$ for $s\rightarrow\infty$, is strongly supported by experiment.
