"desire for the Eucharist, i.e. spiritual communion, is totally different from the union by faith in Christ [(alternatively, union by faith with Christ)] taught by [some] Protestants".

 "le désir de l'eucharistie ou la communion spirituelle est totalement different de l'union par la foi au Christ, enseignée par les protestants.…"

     Louis de Bazelaire, "Communion spirituelle," Dictionnaire de spiritualité 2.2 (1953), col. 1298 (cols. 1294-1300).  Whether de Bazelaire gets his sole-case-in-point-Luther right is another matter.  Nor is there, I think, anything wrong with the doctrine of union with Christ by faith.  It's just that it's not to be identified with this "Catholic extra," i.e. the properly Catholic doctrine of "spiritual communion," which is an intense desire for specifically the very "body, blood, soul, and divinity" of Christ that the bread and wine have in substance become.