And occasionally great pleasure and satisfaction is afforded both patient and doctor when some sufferer calls up on the ’phone at two or three in the morning and inquires what finger to press to relieve the pain of a certain tooth, especially when the advice given has been followed by relief. [Illustration: FIG. 31--Hand and arm, left eyelid and chin, decorated with stickpins after the patient has anesthetized the left side of the body by pressure on the left inferior dental nerve.] [Illustration: FIG. 32--A lighted match is held beneath patient’s right great toe, anesthetized through pressure on the inner surface of the jaw in the first zone.] It has been for many years a quite general piece of knowledge among dentists that the application of menthol to the mucous membrane of the nose, on the same side as an aching tooth, would very frequently stop the toothache. If dentists will now apply a slight elaboration of this bit of zone analgesia technic they may possibly save themselves many gray hairs. What their patients will save in agony, apprehension, and the drain on their vitality cannot be even estimated. CHAPTER 17. ZONE THERAPY--FOR DOCTORS ONLY. We grind and grit our teeth during paroxysms of pain. When we bump our shins against a rocking-chair that has taken point of vantage directly in our path, immediately we clasp the offended shin. In the days before the blessed era of nitrous-oxide and local anesthetics, when the muscular dentist leaned toward the door with our pet tooth in the firm embrace of shiny forceps, we helped him to the utmost by gripping the arms of the chair with vise-like clutch. This maneuver seemingly had no more connection with tooth extraction than have the effulgent rays of the moon upon the pumpkin crop. But we felt our duty, and we did it. When fury and anger sweep us in their red flame, and gentle, familiar aspects of nature take on the hue of blood, we clench our fists until the nails are driven deep into the flesh. In the first shock of the agony of bereavement, or during those cruel dragging hours when we are adjusting ourselves to living with our hearts torn asunder, we clasp our hands in frenzy. For ages we have been doing these things because they are natural and apparently inevitable. We did them automatically, without knowing why. But now we know we do them because they are instructive and scientific. We do these things involuntarily and automatically because they relieve pain or nerve tension--because they produce a form of analgesia, or pain-deadening, similar to that which follows the injection of water or some anesthetic solution into a sensory nerve. Six years ago I accidentally discovered that pressure with a cotton-tipped probe on the mucocutaneous margin (where the skin joins the mucous membrane) of the nose gave an anesthetic result as though a cocaine solution had been applied.