The answer of defendant shall consist of an original answer, and such supplemental answers as may be necessary, in the course of pleading by the parties to the suit. The original answer and the supplemental answers shall be indorsed, so as to show their respective positions in the process of pleading, as "original answer," "defendant's first supplemental answer," "defendant's second supplemental answer," and so on, to be successively numbered, named and indorsed.