COMMENT ON ROLE OF HEAVY MESON-EXCHANGE IN NEAR-THRESHOLD NN-]D-PI

In a recent paper by Horowitz [Phys. Rev. C 48, 2920 (1993)] a heavy m eson exchange is incorporated into threshold NN-->d pi to enhance the underestimated cross section. However, that calculation uses an unjust ified assumption on the initial and final momenta, which causes an ove restimate of this effect by a factor of 3-4. Further, I point out that the inclusion of the Delta(1232) isobar increases the cross section s ignificantly even at threshold.