From the Supplement, compiled after Aquinas’s death from his Commentary on the Sentences and transcribed here from the 1917 to 1922 printings. About the Supplement.
Text: Summa Theologiae, Supplement to the Third Part (Supplementum Tertiae Partis), transcribed from Internet Archive scans, translated by the Fathers of the English Dominican Province. The Supplement, compiled after Aquinas’s death from his earlier Commentary on the Sentences, in the same English Dominican translation as the Gutenberg Parts. Transcribed by Bibliotheca Catholica from the OCR of four Internet Archive scans of the pre-1931 printings (Questions 1 to 33 from the 1917 Washbourne and Benziger volume, 34 to 68 from the 1922 volume, 69 to 86 from the 1921 volume, and 87 to 99 from the 1922 Benziger volume), with OCR errors corrected and doubtful passages marked, not rewritten. 99 questions and 446 articles. The two appendices printed after Question 99 are not included. Sources, SHA-256 of each OCR file, and the method are in the source record. Rights: Public domain (US)
The Supplement is not a Project Gutenberg text. It is Bibliotheca Catholica’s transcription of public-domain scans at the Internet Archive; obvious OCR errors were corrected, and passages marked “OCR uncertain” could not be confidently corrected, so check them against the linked scan page.
Objection 1: It seems that this sacrament ought to be given to children. Because children suffer from the same ailments sometimes as adults. Now the same disease requires the same remedy. Therefore this sacrament should be given to children the same as to adults.
Obj. 2: Further, This sacrament is given in order to remove the remnants of sin, whether original or actual, as stated above (Q. XXX., A. i). Now the remnants of original sin are in children. Therefore this sacrament should be given to them.
On the contrary, This sacrament should be given to none but those to whom the form applies. But the form of this sacrament does not apply to children, since they have not sinned by sight and hearing; as expressed in the form. Therefore this sacrament should not be given to them.
I answer that, This sacrament, like the Eucharist, requires actual devotion in the recipient. Therefore, just as the Eucharist ought not to be given to children, so neither ought this sacrament to be given to them.
Reply Obj. 1: Children's infirmities are not caused by actual sin, as in adults, and this sacrament is given chiefly as a remedy for infirmities that result from sins, being the remnants of sin as it were.
Reply Obj. 2: This sacrament is not given as a remedy for the remnants of original sin, except in so far as they gather strength, so to speak, from actual sins. Hence from the very form it appears that it is given chiefly as a remedy for actual sins, which are not in children.
_______________________
Also online, linked only: the same translation at New Advent and the Latin text at Corpus Thomisticum. Neither is copied here.