As to authentic-text purity: the Hebrew was not corrupted in the prophets', Apostles', or Jerome's ages
Second, Sacred Scripture is perfect as to the purity of the authentic text. Ours have shown this clearly, and against Gordon Huntly's blasphemies the most learned Salomon Glassius especially has solidly proved it in his Sacred Philology.
For the Hebrew text of the Old Testament was not corrupted in the prophets' time: they knew they were not allowed to change or innovate even the least thing in the law (as the Talmudists note at the end of Leviticus 27); nor would they have suffered that crime to be done by others; nor could corruption have been attempted in the authentic exemplar without them.
Nor was it corrupted from the prophets' time onward: because already from Ezra the Masora was added, and because Christ and the Apostles, most sharp-eyed Aristarchuses of false interpretations of the law, would without doubt have noted a corruption of the context if there had been any — as Origen on Isaiah book 8, Jerome on Isaiah 6, and Augustine City of God 15.13 urge. Nor from the Apostles' time: whether we look to the megilloth-sopher (Psalm 40:8) and the Hebrews' handwritten Bibles, or to the Masora, we find nothing but God's marvelous providence and the Jews' stupendous fidelity and most exquisite diligence in guarding the Bibles — of which Josephus Against Apion and Eusebius Church History 3.10 testify that any Jew would rather die a hundred times than suffer the law to be changed in any point.
Nor in Jerome's age (Ribera on Hosea 9: if the codices were then corrupted when Jerome published the Latin translation, the church does not have the true Scripture). Nor in today's Jewish manuscript Bibles — so great is the consent that not even one book of Scripture written by a Jew's hand can be produced that either lacks something the others have or adds what the others lack.
Latin
Secundo, sacra Scriptura perfecta est quantum ad textus authentici puritatem. Hanc nostri luculenter demonstrarunt & contra blasphemias Gordoni Huntlaei imprimis doctissimus Sal. Glassius philologia sacra solide evicit. Nam Hebraeus textus V.T. non corruptus fuit tempore prophetarum, qui norunt sibi licitum non fuisse vel minimum in lege mutare & innovare (ut notant in Lev. 27 ult. Thalmudistae); neque, ut hoc scelus ab aliis patraretur, passi fuissent, neque sine illis in authentico exemplari depravatio tentari potuisset. Neque corruptus fuit a tempore prophetarum: quia jam ab Esdra Masora addita fuit, & quia Christus & Apostoli falsarum legis interpretationum Aristarchi oculatissimi, contextus corruptionem, si qua fuisset, procul dubio notavissent (id quod Origenes l.8. in Esaiam, Hieronymus in cap. 6. Es., Augustinus l.15. de Civ. Dei cap.13 urgent). Neque a tempore Apostolorum: quia sive megilloth-sopher (Ps. 40.8) & manu scripta Hebraeorum Biblia, sive Masoram respiciamus, nihil nisi mirandam Dei providentiam & stupendam Judaeorum fidem & exquisitissimam in custodiendis Bibliis diligentiam deprehendimus, de qua Josephus contra Apionem & Eusebius l.3. Eccl. hist. c.10 testatur, quemlibet Judaeum centies potius moriturum quam ut pateretur legem in aliquo mutari. Neque Hieronymi aetate (Ribera in Hos. 9: si tunc depravati erant codices cum Hieronymus translationem Latinam edidit, non habet ecclesia veram scripturam). Neque hodierna Judaeorum MS. Bibliorum — tantus est consensus ut ne unus quidem scripturae liber proferri possit manu Judaei conscriptus, cui vel desit quicquam quod in aliis habeatur vel addatur quod aliis deest.