Except as provided in section twenty-one of this article, no person shall own, keep or harbor any dog known by him to be vicious, dangerous, or in the habit of biting or attacking other persons, whether or not such dog wears a tag or muzzle. Upon satisfactory proof before a circuit court or magistrate that such dog is vicious, dangerous, or in the habit of biting or attacking other persons or other dogs or animals, the judge may authorize the humane officer to cause such dog to be killed.