Communion in Both Kinds

VC has a good post on laws against child drinking and communion, with comments on communion in both kinds. The Roman position seems to be that it is like priestly celibacy a policy strictly enforced by the Church but allowed or not depending on circumstances of the age. The Council of Constance decrees condemned this and other Wylclifite ideas as being against church commands, not as heresy in itself.

....although Christ instituted this venerable sacrament after a meal and ministered it to his apostles under the forms of both bread and wine, nevertheless and notwithstanding this, the praiseworthy authority of the sacred canons and the approved custom of the church have and do retain that this sacrament ought not to be celebrated after a meal nor received by the faithful without fasting, except in cases of sickness or some other necessity as permitted by law or by the church. Moreover, just as this custom was sensibly introduced in order to avoid various dangers and scandals, so with similar or even greater reason was it possible to introduce and sensibly observe the custom that, although this sacrament was received by the faithful under both kinds in the early church, nevertheless later it was received under both kinds only by those confecting it, and by the laity only under the form of bread. For it should be very firmly believed, and in no way doubted, that the whole body and blood of Christ are truly contained under both the form of bread and the form of wine. Therefore, since this custom was introduced for good reasons by the church and holy fathers, and has been observed for a very long time, it should be held as a law which nobody may repudiate or alter at will without the church's permission. To say that the observance of this custom or law is sacrilegious or illicit must be regarded as erroneous. Those who stubbornly assert the opposite of the aforesaid are to be confined as heretics and severely punished by the local bishops or their officials or the inquisitors of heresy in the kingdoms or provinces in which anything is attempted or presumed against this decree, according to the canonical and legitimate sanctions that have been wisely established in favour of the catholic faith against heretics and their supporters.

See too the Catholic Encylopedia on Utraquism.