I haven't posted anonymously until now. I didn't realize I needed to press that little checkbox! I have recopied it here so that it is under my account.
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Laudislaus has already more than sufficiently addressed the commonly accepted practice. One should prefer to use the gilded spoon, as the Easterners do, instead of allowing a layperson to handle a chalice, even with gloves, due to
admiratio populi and the irreverence it may occasion. I believe I recall Prof Kwasniewski suggesting another way one could do this in a "traditional manner", although somewhat adapted, by using the fistula. Or even a third way, before considering allowing a layman to hold the chalice, is to have the priest gently tilt the chalice for the communicant, while the latter holds a purificator; this would also be preferable before allowing laity to handle the chalice.
And I believe Laudislaus or someone else also noted the important link between gluten intolerance and modern "Big Ag" practices (GMO, glyphosate, etc.).
But for those who were wondering about some of the pre-VII sources that address this, here are just a few I have on hand.
Someone cited Dom Bachofen's commentary on the 1917 Code regarding canon 852, but there was an exception made in 1959, published in the
Canon Law Digest, volume V, 434:
The Holy Office has received the petition of Anne T., who desires to receive Holy Communion, but finds it difficult to do so because she suffers from a severe allergy to wheat in all its forms. After careful consideration of all the circuмstances of the case, this Supreme Sacred Congregation has decreed: “Favor granted whereby the petitioner may receive Holy Communion in the Oriental rite under the species of wine only; opportune safeguards are to be used to avoid wonderment on the part of the faithful.” (12 Dec 1959)
Homiletic and Pastoral Review, volume 62, cites this decree in its article "Allergy and Communion under One Form" (April 1962).
Theological Studies also summarized the common pre-VII practice/commentary in volume 24 (1963):
1. Communion under wine may be administered in extreme cases as viaticuм for someone who cannot swallow solids.
2. The above decree of the Holy Office. But note it mentions several points that one does not see in today's application:
a. It must be in an Oriental rite. This is practically impossible given the geographical distribution of traditional Latin Masses vis-a-vis Eastern rites; hence it may prudentially be disregarded. In saner circuмstances, things would be different.
b. Safeguards must be kept to avoid admiratio populi ("amazement of the people" or in otherwords, the shock that naturally would come over the faithful upon seeing something divergent from what is normal or expected). Other commentators also mention avoiding as far as possible any scandal or irreverence. This is also something one does not often see in traditional chapels that distribute under the species of wine. A good way to avoid this admiratio would be to distribute the Precious Blood outside of Mass, say afterwards when most people have left, but I suspect this isn't done because many would say it is too practically inconvenient for the priest and/or faithful. Most of the reactions here evince what the tradition was warning against by distributing in front of everyone.