It is unlawful for any person to practice or offer to practice medicine and surgery as an osteopathic physician and surgeon in this state without a license or permit issued by the West Virginia Board of Osteopathic Medicine: Provided, That any license heretofore issued under the laws of this state, authorizing its holder to practice osteopathy and surgery, shall in no way be affected by the enactment of this article; except that the holder of every such license shall be subject to all of the provisions of this article respecting the requirements and obligations herein prescribed for the continuance in force of such license.