OBS. 7. Style sometimes requires the omission of the comma before and, or, nor, when one of these connectives precedes the last term of a series: as “Shakspeare, Butler and Bacon have rendered it extremely difficult for all who come after them to be sublime, witty or profound.” But when the words are all in the same predicament, the comma should be inserted; e. g.,—if you wish to state that three certain persons are wise, you would point thus:
“Thomas, Richard, and John are wise.”
But if Richard and John are the Solons, and you wish to inform Thomas of that fact, you would point thus:
“Thomas, Richard and John are wise.”
So, in the first example under b, if it is desired to qualify the three adjectives by the phrase “in the highest degree,” the comma after witty must stand: “in the highest degree sublime, witty, or profound.” But if that phrase is intended to apply to sublime only, the pointing should be thus: “in the highest degree sublime, witty or profound.”
15. Phrases, clauses, and words, inverted, or otherwise not in their natural position, generally require to be set off by a comma.
Into this illustrious society, my friend was joyfully received.
When we quarrel with ourselves, we are sure to be losers.
To satisfy you on that point, I will make a short argument.
He, like the world, his ready visits pays,