Under the maxim volenti non fit injuria, a surgeon may inflict upon the body of his patient what otherwise would amount to a technical battery. The consent of the patient justifies the application of force to his person. Zoterell v. Repp, 187 Mich. 319, 153 N.W. 692; Robinson v. Crotwell, 175 Ala. 194, 57 So. 23; King v. Carney, 85 Okla. 62, 204 Pac. 270; POLLOCK, TORTS, 159; BURDICK, LAW OF TORTS, 110; TORTS, RESTATEMENT No. 1, Sec. 66. A generally accepted limitation to this doctrine is that consent to the commission of an unlawful act upon the person will absolve from neither criminal nor civil liability. POLLOCK, TORTS, 160; CHAPIN, TORTS, 116. See however, TORTS, RESTATEMENT No. 1, Sec. 75 & 76. On the other hand the general rule is that unless the patient consents to the operation, the surgeon is liable for substantial damages, even though the operation was skillfully performed, was successful and of great benefit to the patient. The unauthorized invasion of the plaintiff's person is the gist of this action.