The object of an amendment, as contra-distinguished from a supplemental petition or answer, is to add something to, or withdraw something from, that which has been previously pleaded so as to perfect that which is or may be deficient, or to correct that which has been incorrectly stated by the party making the amendment, or to plead new matter, additional to that formerly pleaded by the amending party, which constitutes an additional claim or defense permissible to the suit.