The sufficiency of any pleading, in law or equity, may be tested by a demurrer. Objections to the filing of any pleading, because of insufficiency, are abolished. The form of a demurrer shall be: The defendant (or plaintiff) says that the declaration (or other pleading) is not sufficient in law, for the following reason (or reasons): All demurrers in civil cases shall be in writing and shall state specifically the grounds of demurrer relied on, and no grounds shall be considered other than those so stated, except by the court of its own accord, but the demurrant may, by leave of the court, amend his demurrer by stating additional grounds, or otherwise, at any time before the trial at law or final hearing in equity. When a party demurs to any pleading, the demurrer shall at once be set for argument.