Style manual: Archaic spellings and styles of punctuation in direct quotations from older works are to be preserved if they occur infrequently and do not interfere with a reader' s comprehension  However, if they occur frequently, the editor may modernize them, inserting a note with an explanation to this effect in the text, or if similar modernizing has been done in more than one quotation, inserting a general statement in the preface
On the other hand, obvious typographical errors in quotations from modern works may be corrected without explanation
An editor may modernize an archaic spelling of a word found in a modern work without providing an explanation.