A physician or a dentist, in good faith and in the course of his professional practice only, may prescribe, administer, dispense, mix or otherwise prepare narcotic drugs, or he may cause the same to be administered by a nurse or interne under his direction and supervision.
A veterinarian, in good faith and in the course of his professional practice only, and not for use by human beings, may prescribe, administer, dispense, mix or otherwise prepare narcotic drugs, and he may cause them to be administered by an assistant or orderly under his direction and supervision.
Any person who has obtained from a physician, dentist, or veterinarian any narcotic drug for administration to a patient during the absence of such physician, dentist, or veterinarian, shall return to such physician, dentist, or veterinarian any unused portion of such drug, when it is no longer required by the patient.