ALL ABOUT HOLY eucharist. document released at Rome, from the offices of the Congregation for the Doctrine of the Faith on September 14, 1994.
Communion in the hand was the norm for most of the first millennium. Because of the dangers of misuse and the growing concern for reverence, the practice of giving the Host on the tongue was introduced about the ninth century.
The present practice of giving communion in the hand dates from 1969, when Pope Paul VI opened the way for episcopal conferences who wished to reintroduce the practice. Permission was granted to the U.S. bishops in 1977.
There is nothing intrinsically more reverent about reception on the tongue or less reverent about receiving in the hand. Reverence or irreverence are generally determined by other factors:
the spiritual attitude of the recipient,
the demeanor of the one giving communion,
the adequacy of Eucharistic understanding, and
the manner in which the Eucharistic elements are treated both within and outside Mass.