Dips and Spikes in dσ/dt for High Energy Exchange Reactions**Invited talk presented at the V-th “Recontre De Moriond,” Meribel-Les-Allues, France, March 9-20, 1970. Submitted for the Amos de-Shalit Memorial Volumes of Annals of Physics, Volumes 63 and 66, 1971, this article was inadvertently omitted from these dedicatory issues. Work supported in part by Stiftung Volkswagenwerk.