Any person shall be regarded as practicing medicine within the meaning of this article who (a) shall as a business treat, operate on or prescribe for any physical ailment of another, (b) shall engage in any branch or specialty of the healing art or (c) shall diagnose, cure, relieve in any degree or profess or attempt to diagnose, cure or relieve any human disease, ailment, defect, abnormality or complaint, whether of physical or mental origin, by attendance or advice, by prescribing, using or furnishing any drug, appliance, manipulation, adjustment or method or by any therapeutic agent whatsoever.